TEXT: a dozen arcane spell components • page 1
  a dozen arcane 
  spell components
  by philip reed
  A Dozen Arcane Spell Components © 2019, 2020 Philip Reed, all rights reserved. 
  Title page art by Tithi Luadthong, used under license from Shutterstock.com.
  All other artwork copyright Daniel Comerci, used under license. danielcomerci.com
  One of my earliest D20 System PDFs was devoted to the 
  idea that wizards could amplify the power of their spells 
  by adding special arcane spell components to the cast-
  ing ritual. 101 Arcane Spell Components was one of my 
  many hits well over a decade ago, so it should come as 
  no surprise that I decided to tackle the subject again.
  Where today’s approach to spell components deviates 
  from my original work is in two very specific ways:
  • These “rules” are systemless in nature, meaning that 
  the gamemaster must craft the actual in-game effects 
  for each of the described items. This isn’t as complicat-
  ed or challenging as it may sound, though, because I 
  do provide some loose guidance.
  • I’ve given each of the described arcane spell compo-
  nents a full page so that each can include suggestions 
  on how the items may affect spells, separated by 
  school of magic. In many instances, a component only 
  affects spells of three or four different schools of mag-
  ic. As always, adjust the specifics to suit your needs.
  It is my hope that these spell components both find 
  their way into your campaign and inspire you to create 
  special spell components of your own. My absolute fa-
  vorite feature of roleplaying games is that the GM is free 
  to – in fact, encouraged to – create whatever comes to 
  mind, and it is in that spirit of free and wondrous magic 
  that the arcane spell components that follow were gen-
  erated. Please let that wonder infect your game.
  
  a dozen arcane spell components • page 2
  anatomy of a component
  using the components
  1
  2
  3
  4
  5
  1. A title, to help set the mood.
  2. Descriptive text and overview of the sug-
  gested arcane spell component.
  3. A recommended gold piece value. At 
  times, this is a range of values. As always, 
  the gamemaster should adjust these num-
  bers as necessary for the campaign.
  4. How the arcane spell component affects 
  spells depending on the spell’s school of 
  magic. I’ve used the eight schools of magic 
  that are in use by the world’s best-selling 
  fantasy roleplaying game. If your chosen 
  game system does not divide spells into 
  separate schools of magic, use the de-
  scribed effects as best suits your tastes. 
  Perhaps all of the listed effects are avail-
  able to a spell, regardless of school; if this 
  is true, the caster must make a successful 
  magical knowledge check to activate the 
  preferred result.
  5. Every component includes an illustration 
  to give you a better idea of the item’s ap-
  pearance.
  Unlike many of the entries in the A Dozen . . . series, A 
  Dozen Arcane Spell Components offers more game 
  mechanic-like information than it does story and set-
  ting material. That could make using the following pag-
  es a tad challenging, but only if you try to use the com-
  ponents exactly as they have been described.
  Instead of using these arcane spell components as mag-
  ical enhancers for spellcasters in your game world, treat 
  each as a possible adventure hook. Perhaps the player 
  characters do not know the secrets of these items, but 
  they may be hired by a more experienced spellcaster 
  who needs someone to find a specific component.
  Arcane Knowledge. Before a wizard or mage may take 
  advantage of any of these arcane spell components, 
  the character must have an understanding of the com-
  ponent’s influence on the different schools of magic. 
  Each separate component requires an Arcana skill or 
  intelligence check; on a successful check, the character 
  knows of the item’s ability to affect cast spells.
  Bardic Knowledge. Similar in nature to arcane knowl-
  edge, a bardic understanding of the affect that these 
  components may have on spellcasting involves a broad, 
  historical knowledge; such as when a particular caster 
  may have used one of the items in a historical event.
  
  a dozen arcane spell components • page 3
  locked treasure chest
  Bulky and challenging to transport, few spellcasters 
  are willing to tote a locked chest during an adventure, 
  meaning that this item is most often used when casting 
  spells in the safety of a wizard’s laboratory or workshop. 
  The value of the chest itself has little bearing on the spell. 
  Instead, it is the value of the items locked within the 
  chest that directly impact the spell’s strength and effect.
  Value: 1 to an unknown number of gold pieces, all de-
  pendent upon the items within the chest. The chest 
  itself, as well as the lock, must be worth a combined 
  total of at least 50 gold for the following effects to 
  act as described.
  • 
  Abjuration Spells: When consumed in the casting 
  of an abjuration spell, a locked treasure chest ex-
  tends the range and duration of the cast spell. For 
  every 100 gp worth of value of treasure destroyed 
  when the spell is cast, either the range or the dura-
  tion is increased by 10% (caster’s choice). 
  • Conjuration Spells: No effect.
  • Divination Spells: No effect.
  • Enchantment Spells: There is a percentage chance 
  (equal to one-tenth the value of the treasure de-
  stroyed in the casting of the spell) that the boosted 
  spell will both double its range and duration. On a 
  failed percentage check, the chest and treasure are 
  destroyed with no effect on the spell.
  • Evocation Spells: No effect.
  • Illusion Spells: In addition to the cast spell, the wiz-
  ard also casts any first level illusion spell of his choice, 
  regardless of whether or not he knows the spell. This 
  second spell is cast as a free action and ignores all 
  component requirements and any restrictions.
  • Necromancy Spells: The affected spell takes effect 
  as normal, and the caster gains a +1d6 protective re-
  sistance to all attacks. This resistance reduces the hit 
  point damage of any attack – mundane or magical 
  – for 2d4+2 rounds. Additionally, there is a percent-
  age chance equal to one-twentieth the value of the 
  consumed treasure that the wizard automatically re-
  covers access to the just-cast spell.
  • Transmutation Spells: No effect.
  
  a dozen arcane spell components • page 4
  potion vial
  When a potion is brewed, the creator infuses a lot of 
  magical power into the liquid, trapping arcane secrets 
  and ingredients in a small vial or bottle. At times, a wiz-
  ard may choose to unleash that contained power in an 
  unusual manner, by destroying the potion during the 
  casting of a spell rather than drinking the elixer. 
  When consumed as a spell component, the act of cast-
  ing the spell destroys both the liquid and the container, 
  the two consumed in a magical flame that provides lit-
  tle light and extinguishes within seconds.
  Value: The value of a potion varies greatly, depending 
  on the power of the drink as well as the rarity and 
  value of potions on your chosen game world. Gen-
  erally, only potions worth 25 gold or more may be 
  used as an arcane spell component.
  • 
  Abjuration Spells: No effect.
  • Conjuration Spells: The strength and dexterity sta-
  tistics of the summoned being, if it possesses such 
  stats, are increased by 25%, regardless of the value of 
  the destroyed potion. The caster also gains the ben-
  efit of the lost potion, even though the potion was 
  not swallowed.
  • Divination Spells: No effect.
  • Enchantment Spells: No effect.
  • Evocation Spells: The spell’s duration is increased 
  by a 1d3+2 rounds. Additionally, the damage value 
  of the spell, if any, is increased by 1d4+1 points. In the 
  event that the spell has neither a duration or deals 
  damage, the cast spell is automatically returned to 
  the wizard, prepared and ready to cast again with no 
  component requirements at all.
  • Illusion Spells: The affected spell is delayed; it ap-
  pears that the caster’s spell has fizzled and failed. At 
  any time within the next week, the caster may un-
  leash the spell as a free action, even if bound by the 
  hands and gagged, or otherwise immobilized. 
  This is a very handy trick for a wizard who 
  expects that he may be walking into 
  a trap and could very well be cap-
  tured by enemies.
  • Necromancy Spells: No effect.
  • Transmutation Spells: In addition to the cast spell, 
  the wizard immediately prepares/memorizes any 
  transmutation spell of a level no greater than one-
  half the level of the cast spell (round up). The gained 
  spell must be cast/used as per normal casting rules.
  As with all new game 
  rules and ideas, nothing 
  within these pages may be  
  used without GM permission.
  
  a dozen arcane spell components • page 5
  severed hand
  Only a hand that was freshly severed, hacked from a liv-
  ing being within the past hour, will function as detailed. 
  The hand need not be that of the caster, meaning that 
  evil mages who learn of this arcane secret sometimes 
  capture and enslave others to use one of their hands 
  when casting spells. If you confont a wizard who has 
  only single-handed apprentices, you can be sure that 
  the spellcaster is up to no good.
  Value: 75 gold pieces, more if there is a ring on one of 
  the hand’s fingers.
  • 
  Abjuration Spells: No effect.
  • Conjuration Spells: No effect.
  • Divination Spells: No effect.
  • Enchantment Spells: No effect.
  • Evocation Spells: The spell’s damage is doubled 
  when a severed hand is used in casting. This boost in 
  damage is tripled if the hand wears a valuable ring 
  (100 gold or more) about one of its fingers.
  • Illusion Spells: No effect.
  • Necromancy Spells: In casting the spell, the sev-
  ered hand absorbs the spell’s power and prevents 
  the spell from functioning as normal. Instead, 
  the magic transforms the lifeless hand into 
  an animate, moving creature that is under 
  the complete control of the spellcaster. 
  For a number of hours equal to the in-
  telligence score of the wizard, the hand 
  may move about and act as if it were 
  a living monster. The hand has inhu-
  man, magical strength and its control 
  requires all of the wizard’s concentra-
  tion; the wizard must sit completely 
  still and unmoving for so long as the 
  hand remains active. If anything 
  breaks the wizard’s concentration, 
  the hand falls limp and lifeless, the 
  magic broken and over.
  • Transmutation Spells: There is a 10% chance when 
  the spell is cast that the victim who lost a hand will 
  regrow that hand within 1d6+1 days of the incident.
  “It moved on five thick and curiously jointed  
  legs and altogether had such an eery 
  appearance about it, that Kane was  
  spellbound for the moment.”
  – Robert E. Howard,  
  “The Right Hand of Doom”
  
  a dozen arcane spell components • page 6
  magic ring
  There are many different types of magic rings, any one of 
  which may be used in the casting of an arcane spell. The 
  return on investment is low, though, so few spellcasters 
  use a ring as a component except in an emergency.
  To destroy the ring in the casting process, the mage 
  must throw the ring up into the air as the spell is un-
  leashed. The ring instantly vanishes, replaced with a 
  glowing cloud of smoke that lingers over the spellcast-
  er’s head for 1d3 rounds. 
  In some instances, roughly 25% of the time, the cloud 
  slowly settles over the spellcaster, enveloping the body 
  in a shimmering aura of arcane energy that grants the 
  caster a bonus resistance to attacks for 2d4 rounds. 
  During this time, all physical damage inflicted on the 
  spellcaster is cut in half. Once the aura dissipates, the 
  caster’s skin and worn belongings are covered in a light 
  dust that is difficult to wash off. 
  Value: Magic rings have no single value, with the ring’s 
  rarity and power level driving the price more than 
  anything else. Any magic ring may be used as a spell 
  component; the GM may modify the effect as appro-
  priate to the value of the ring.
  • 
  Abjuration Spells: The duration of the impacted 
  spell is doubled. Additionally, the caster automati-
  cally gains the ability to grant any unarmored crea-
  ture or character a magical defense against physical 
  attacks. By successfully touching any unarmored 
  character or creature within one hour of the ring’s 
  destruction, the caster grants the target the bene-
  fit of mage armor, an arcane shell that increases the 
  subject’s armor class or rating (as appropriate to 
  your chosen game system). 
  • Conjuration Spells: No effect.
  • Divination Spells: Once the spell’s duration has 
  expired, the spellcaster is infused with the ability to 
  detect magic, as per the spell of the same name, for 
  a number of hours equal to the character’s intelli-
  gence score. This ability to detect magic is a free ac-
  tion and the magical aura surrounding the detected 
  item is visible to everyone, not just the spellcaster.
  • Enchantment Spells: The spell functions as nor-
  mal, with no change in strength of effect, making it 
  at first appear as if the destruction of the ring was 
  for naught. When the spell expires, the mage imme-
  diately casts it a second time, following most of the 
  standard requirements (if the spell required physical 
  components, those are unnecessary for this repeat 
  casting of the spell). 
  • Evocation Spells: The damage of an evocation 
  spell that has been enhanced by the destruction of 
  a magic ring is increased by 2d6 points. This increase 
  in damage is regardless of whether or not the ampli-
  fied spell – if it required a roll to successfully strike 
  – hits the targeted character or creature. 
  • Illusion Spells: No effect.
  • Necromancy Spells: No effect.
  • Transmutation Spells: The spell is cast as normal, 
  unchanged by the magic ring. At the exact same 
  time, the caster infuses any ally within line-of-sight 
  with the ability to cast the same spell – without need 
  of spellcasting knowledge or any physical com-
  ponents – as if the caster had released the second 
  instance of the spell and not the ally. This second 
  casting must be completed within two rounds, oth-
  erwise the subject suffers 2 points of damage.
  
  a dozen arcane spell components • page 7
  fine statuette
  Small and valuable sculptures that are popular with the 
  wealthy who like to display their excellent taste – and 
  their worth – can be more than simple art objects to be 
  found and traded away for coin. Mages with an under-
  standing of consuming such statuettes in the casting of 
  arcane spells value the art for what it can bring to their 
  magic, rather than the look or price of the item.
  Value: At least 50 gold pieces, though there is effective-
  ly no limit to the value of fine artwork.
  • 
  Abjuration Spells: No effect.
  • Conjuration Spells: The spell has a 50% chance of 
  functioning as described, otherwise the statuette in-
  creases the spell’s duration by one moment for every 
  50 gp worth of value of the art object. In rare instanc-
  es, the statue is not destroyed when the spell is cast. 
  Instead, the statue is transformed into a magical 
  statue that, when touched and the command word 
  spoken, instantly turns the statue into a stone golem 
  possessing the shape of the statue but growing to 
  twice its original size. The caster immediately knows 
  the command word, as well as the power of the new 
  magic item, when the item is formed as a side-effect 
  of its use as a spell component. 
  • Divination Spells: No effect.
  • Enchantment Spells: For the spell’s duration, all en-
  emies within 10’ of the caster must make a successful 
  wisdom check or they become unable to perceive 
  the caster as a threat. So long as the caster does not 
  strike them, they will not attack the wizard.  On a suc-
  cessful check, the caster’s opponents are unaffected 
  by this magical effect and may continue to attack as 
  they normally would. 
  • Evocation Spells: No effect.
  • Illusion Spells: The cast spell is instantly prepared 
  again, memorized and ready for action. If the spell 
  required material components, those are unneces-
  sary for a second casting of the spell if the wizard 
  uses this ability within the next hour. 
  • Necromancy Spells: No effect.
  • Transmutation Spells: The spell’s range is doubled 
  and, for the spell’s duration, the caster assumes the 
  form of the statue though at her original size. If the 
  statue is in any way horrific or frightening, the cast-
  er gains the ability to cause fear in others; all within 
  line-of-sight of the caster must make a successful 
  wisdom check or become frozen with fear until the 
  spell comes to an end.
  
  a dozen arcane spell components • page 8
  burning torch
  Many adventurers carry torches when setting out on 
  adventure, but some may raise an eyebrow when the 
  party’s wizard buys seven or eight torces for use in a sin-
  gle dungeoncrawl. Those in the know understand that 
  the wizard has learned the secret of enhancing spells 
  through the burning of a torch.
  Value: A single torch costs one copper.
  • 
  Abjuration Spells: The cast spell functions as nor-
  mal, and the caster is surrounded by a ring of flames 
  that deal 1d4 points of damage to any who dare try 
  and cross the fiery ring. The caster is immune to the 
  flame’s damage and the ring moves with him, giv-
  ing the spellcaster an offensive weapon with which 
  to push back opponents. The ring of fire completely 
  encircles 5’ around the caster and lasts for one round 
  before it vanishes, leaving behind only a dark smoke.
  • Conjuration Spells: The spell’s range is doubled 
  when the torch is consumed in casting. There is no 
  other effect.
  • Divination Spells: No effect.
  • Enchantment Spells: No effect.
  • Evocation Spells: Any fire spells cast when a burn-
  ing torch is used as an arcane spell component see a 
  +1d6 increase in damage. When used in this way, the 
  flame of the torch lances out and joins the arcane 
  fire, the two melding into a destructive blast that has 
  a 1 in 20 chance of knocking down human-sized and 
  smaller opponents who are struck by the attack. The 
  wizard is left holding the stump of the torch, 
  which falls to ash as soon as it is dropped 
  or touched.
  • Illusion Spells: No effect.
  • Necromancy Spells: The cast spell takes effect as 
  normal, with no modification, when a burning torch 
  is used as an arcane spell component. In addition 
  to the spell’s normal effect, the caster is surrounded 
  by a smokey cloud that burns the eyes of others; a 
  successful constitution check must be made to re-
  sist the smoke’s effect. The smoke slowly expands, 
  extending in all directions by 5’ each round after the 
  spell is exhausted. The cloud lin-
  gers for 2d4+1 rounds.
  • Transmutation Spells: 
  No effect.
  Any of the abilities described within these pages 
  may be reworked as the GM sees fit. Never forget 
  that, as the gamemaster, the world is yours to do 
  with as you wish. All of the ideas presented herein 
  exist solely to inspire your own imagination.
  
  a dozen arcane spell components • page 9
  stuffed coin pouch
  Many characters carry coin pouches, though few are 
  willing to sacrifice those hard-earned coins simply to al-
  low the party’s wizard to boost the power of a cast spell. 
  For this item to work as an arcane spell component, 
  it must be stuffed with coins of no lesser a value than 
  gold; even a single copper piece in the pouch causes 
  the spell to misfire and the coins – and purse – to be 
  completely erased from existence.
  If there are gemstones in the pouch, along with coins, 
  the component still acts as described. Any other items 
  mixed in with the coins are treated as copper piec-
  es (meaning the spell misfires with no effect and the 
  pouch and all items are forever lost).
  Value: The value ranges from a few dozen gold coins to 
  tens of platinum coins, with the only limit being the 
  size of the pouch and the contained coins. 
  • 
  Abjuration Spells: For every dozen gold pieces in 
  the pouch (or equivalent monetary value of other 
  coins), the spell’s duration is increased by a single 
  round. For the duration, the caster reduces the dam-
  age of all incoming physical attacks by 2 points.
  • Conjuration Spells: No effect.
  • Divination Spells: The spell functions as normal 
  and the caster gains immediate access to the spell 
  charm person which may be cast as a free action. 
  The bonus charm person spell must be used within 
  2d6 rounds of the cast spell’s end; failure to use the 
  charm person spell in the allotted time means that 
  the spell is lost; the caster suffers two damage.
  • Enchantment Spells: No effect.
  • Evocation Spells: No effect.
  • Illusion Spells: No effect.
  • Necromancy Spells: Any undead created/raised 
  are more powerful thanks to the coins that are sac-
  rificed to the gods of death. Undead creations may 
  take twice the normal number of hits before being 
  destroyed, have the damage that they can inflict in-
  creased by 25%, and the duration of the time on this 
  world (if a duration is relevant) is doubled.
  • Transmutation Spells: Only one-half of the coins 
  are consumed when the spell is cast. Any remain-
  ing coins are a molten, fused slag of metal that may 
  prove valuable to a craftsman or artist. The spell’s 
  range and duration are each increased by 25% 
  (round up).
  
  a dozen arcane spell components • page 10
  magic scroll
  A wizard who uses a magic scroll as an arcane spell 
  component, rather than reading and casting the spell 
  locked to the scroll’s parchment, knows well the secrets 
  of magic. While there are times when a scroll’s spell may 
  be more powerful than the spell the wizard is choos-
  ing to cast, it is the way in which the scroll amplifies the 
  spell that makes the sacrifice of the item well worth it.
  Value: As with magic rings and potions, the value of a 
  scroll can vary widely. As with everything magic, the 
  value relies solely on the power of the spell that is 
  inscribed on the magic scroll.
  • 
  Abjuration Spells: The spell’s duration is doubled.
  • Conjuration Spells: The scroll is not destroyed. In-
  stead, an exact duplicate of the scroll forms in the 
  wizard’s open hand, leaving the caster holding two 
  copies of the same scroll once the spell (which acts 
  as normal) expires. Neither scroll may be used as an 
  arcane spell component.
  • Divination Spells: A divination spell amplified by 
  the destruction of a magic scroll also grants the cast-
  er the ability to cast a second divination spell with-
  out the need to memorize or otherwise prepare the 
  spell. The caster must know the second spell, or pos-
  sess a scroll or book that details the spell, in order for 
  this to work. The power of the second spell cannot 
  exceed the level of the spell described on the scroll 
  that is destroyed during casting.
  • Enchantment Spells: The spell’s range is doubled.
  • Evocation Spells: Once the cast spell ends (which 
  functions as described), the scroll bursts into blue 
  flames that spread out 20’ in every direction, deal-
  ing a single point of damage to everything that they 
  strike. There is a percentage chance equal to the 
  caster’s intelligence score that the caster may con-
  trol this magical flame, pulling the fire to his hands 
  (after the initial burst that casues damage to those 
  around him) and unleashing it again and again as an 
  arcane blast that deals 1d4 damage every round for 
  3d4+1 rounds.
  • Illusion Spells: The spell’s duration is doubled.
  • Necromancy Spells: The spell’s effects are unaf-
  fected by the destroyed scroll and, additionally, the 
  caster gains the ability to fire a necromantic blast 
  that deals 2d8 points of damage against any target 
  he can see. This magical attack requires a successful 
  ranged attack roll; if the caster fails in the attack, the 
  blast redirects its energy and inflicts 1d8 points of 
  damage to the spellcaster. The caster then forever 
  carries a burn mark somewhere on his body.
  • Transmutation Spells: The spell’s duration and 
  range are both doubled, and the caster gains the 
  power of flight for both the spell’s duration and an 
  additional 2d6+2 rounds. When flying, the power is 
  treated as per the spell of the same name.
  
  a dozen arcane spell components • page 11
  shattered sword
  Most swords are durable, powerful weapons that have 
  been forged to withstand the challenges of combat 
  against armored foes. Swords rarely break in battle, and 
  rarer still are the times when a sword shatters into sev-
  eral pieces, leaving the warrior standing there with a 
  near-useless weapon.
  Those swords that are broken into multiple parts have 
  value to spellcasters who know the secrets of their use 
  as an arcane spell component.
  Value: Nothing, usually, though a wizard who knows 
  how to use the shattered sword as a material com-
  ponent may pay up to 100 gold for the item.
  • 
  Abjuration Spells: When cast, the spell functions as 
  normal and the pieces of the shattered sword levi-
  tate in front of the caster. As soon as the spell ends, 
  each of the pieces of the shattered sword – 1d4+2 
  pieces in total – become an arcane weapon that the 
  caster may direct at any enemy. Firing one of 
  these sword parts is a free action and deals 
  1d4+2 damage to the chosen target. 
  No attack roll is necessary; the levitat-
  ing bit of sword strikes its target with-
  out fail. Any bits of the sword that are 
  not used within two rounds fall to the ground and 
  turn to dust, forever losing their magical property.
  • Conjuration Spells: The spell acts as normal and, 
  once it comes to an end, the sword is reformed and 
  made whole. It is now a +1 magical weapon that 
  is otherwise identical to what it was before it was 
  shattered into bits.
  • Divination Spells: The duration of the spell 
  is doubled as the bits of the shattered sword whirl 
  around the caster, creating a defensive barrier that 
  reduces all physical damage by four points for the 
  spell’s duration. Anyone, ally or foe, attempting to 
  pass through the spinning bit of the shattered sword 
  immediately suffers 2d4 points of damage and one 
  bit of broken sword drops to the ground, exhaust-
  ed and useless. There are 1d4+ 2 bits total, and if 
  enough enemies rush the caster, they can bring an 
  end to this spinning death before the spell expires.
  • Enchantment Spells: No effect.
  • Evocation Spells: The spell’s damage is doubled. 
  The sword is instantly consumed in a flash of arcane 
  light that blinds those who fail a constitution check.
  • Illusion Spells: No effect.
  • Necromancy Spells: No effect.
  • Transmutation Spells: No effect.
  
  a dozen arcane spell components • page 12
  locked dungeon door
  Where a thief may be useful when it is time to pick a 
  door’s lock, the wizard who possesses knowledge of this 
  particular arcane spell component becomes invaluable 
  when it is time to get through the next locked door. 
  By placing both hands on the locked door when cast-
  ing a spell, the wizard absorb’s the energy of the lock, 
  channeling the security of the lock into the spell. Un-
  like many spell components, the act of using a locked 
  door in casting does not destroy the door; instead, only 
  the lock is affected by this power. Once used in this way, 
  the door’s lock and handle are forever gone. Someone 
  could come through later and replace the hardware.
  Value: It is difficult to put a price on something like 
  a door and lock, especially considering that this 
  power only works with doors that are below 
  ground and, usually, in some forgotten dun-
  geon or other.
  • 
  Abjuration Spells: The spell becomes 
  locked for 1d6+3 days, meaning that no 
  matter how hard the wizard tries, the 
  spell may not be memorized or prepared 
  until the time has expired. When cast, 
  the spell’s duration is increased by 1d4 
  times; and yes, this does mean that the du-
  ration could be unchanged.
  • Conjuration Spells: Once the affected 
  spell has ended, the caster gains the power 
  to create a duplicate of the door – including 
  a functional lock – anywhere within sight 
  of the original door. This power to create a 
  new door must be used within one minute 
  of the expiration of the cast spell; after that 
  minute, the power is lost. The new door is 
  every bit as durable as the original and, 
  when brought into existence, the dun-
  geon’s walls close in to forever alter the 
  shape of the complex. The new door cannot be 
  used as an arcane spell component.
  • Divination Spells: No effect.
  • Enchantment Spells: No effect.
  • Evocation Spells: No effect.
  • Illusion Spells: The cast spell is unaffected by this 
  component. Instead, the mage gains the ability to, 
  as a free action, project an illusion of the door any-
  where within line-of-sight. The door illusion remains 
  active for three hours.
  • Necromancy Spells: No effect.
  • Transmutation Spells: No effect.
  
  a dozen arcane spell components • page 13
  valuable gemstones
  Whether raw and uncut, or finely crafted and polished, 
  gemstones make an excellent item to enhance the 
  power of many arcane spells. It is said that some mag-
  es grow addicted to the power granted by gemstones 
  that are consumed in spellcasting, leading those 
  spellcasters to do all that they can to acquire 
  more and valuable stones. 
  Unfortunately for those same wizards, 
  the addiction is dangerous. Keep 
  track of how many times that a 
  wizard uses a gemstone as an 
  arcane spell component. The 
  next time that the charac-
  ter uses a gem as a spell 
  component, there is a 
  percentage chance equal 
  to the number of previ-
  ous uses that the power is 
  too much for the character to handle; the spell fizzles 
  without effect and the caster suffers 2d4 points of dam-
  age in the accidental casting of the spell.
  Value: Not surprisingly, there is no single set value for 
  gemstones. Consult your preferred game’s treasure 
  tables for a possible value for gems by type.
  • 
  Abjuration Spells: No effect.
  • Conjuration Spells: The gemstone replaces any 
  other material components that the affected spell 
  may require. Once cast, the spell’s duration is dou-
  bled if the caster makes a successful arcane knowl-
  edge check; on a failed check, the spell’s duration is 
  cut in two. 
  • Divination Spells: In addition to the spell’s normal 
  effect, the caster also gains Clairvoyance, as per the 
  spell of the same name, with a duration equal to 10% 
  of the gemstone’s gold piece value. The caster must 
  choose hearing or seeing when the Clairvoyance 
  power activates. 
  • Enchantment Spells: No effect.
  • Evocation Spells: All damage inflicted by the af-
  fected spell is increased by one point for every 25 
  gold pieces of value of the consumed gemstone 
  (round damage down, minimum of one point).
  • Illusion Spells: The spell’s range is doubled and 
  duration is cut in half, unless the caster makes a suc-
  cessful intelligence check (in which case the dura-
  tion is unaffected). Additionally, the spellcaster gains 
  the power of invisibility, as per the spell of the same 
  name, with a duration in combat rounds equal to 
  the caster’s intelligence score. If the wizard attacks 
  or casts a spell while under the invisibility power, the 
  invisibility is broken and the wizard is once again vis-
  ible to the world.
  • Necromancy Spells: Any spell that animates and 
  creates undead sees its duration doubled. Undead 
  creatures brought into service thanks to the power 
  of the gemstone glow red and the damage of their 
  unarmed attacks is increased by +2 points. Those 
  creatures also have a 10% chance of being automat-
  ically immune to bladed weapons.
  • Transmutation Spells: No effect.
  
  a dozen arcane spell components • page 14
  ring of keys
  Jingling and jangling together, the clinking of metal 
  a dangerous sound that travels far in any dungeon, a 
  ring of keys can be a useful tool for those spellcasters 
  who know the secret to changing the keys from their 
  physical form into arcane energy that can amplify the 
  strength of a cast spell.
  To work, the ring must have at least three keys; any few-
  er than that and the spell misfires without effect and 
  the keys turn hot to the touch, burning any who dare 
  to grab them before the metal has cooled (which takes 
  roughly 15 minutes).
  NOTE: Only metal keys will work as described.
  Value: The exact value of a key depends most on the 
  lock that it can open. The key that opens a locked 
  treasure vault is far, far more valuable than the key 
  that the baker uses to lock his shop at the end of the 
  day. Only keys that have meaning – keys that unlock 
  places and things that are still in use – will work as 
  detailed below.
  • 
  Abjuration Spells: No effect.
  • Conjuration Spells: No effect.
  • Divination Spells: When the spell is cast, all but 
  one of the keys are destroyed and vanish forever. The 
  final key, still connected to the ring, is now a magic 
  item that grants anyone holding it the ability to cast 
  tongues, as per the spell, once per day as a free ac-
  tion. This allows the user to speak and understand 
  any language for one hour.
  • Enchantment Spells: As the spell is cast, the ring 
  of keys levitates between the caster and the 
  subject, the clanking and clanging of the 
  keys growing louder and louder, forcing 
  those within line-of-sight of the event 
  to cover their ears of suffer a negative con-
  dition such as being shaken by the sound. The 
  keys continue in this manner for the the duration 
  of the spell. Once the spell is exhausted, the keys are 
  destroyed in a magical fire. The caster is immune to 
  the clanging of the keys.
  • Evocation Spells: No effect.
  • Illusion Spells: In additon to doubling the spell’s 
  range, the destruction of the keys grants the caster 
  the ability to see invisible objects and creatures for 
  the spell’s duration. When the spell expires, there is 
  a 25% chance that the see invisible power will linger 
  on, staying with the caster for 2d6+2 rounds.
  • Necromancy Spells: No effect.
  • Transmutation Spells: 
  Any mundane 
  weapon that the 
  caster touches 
  within 1d6 
  rounds of the 
  spell ending 
  is ensorcelled, 
  inflicting an extra 
  +1d4 damage 
  for the next two 
  hours.
  
SOURCE: textdata/thevault/Dungeons & Dragons [multi]/5th Edition (5e)/3rd Party/A dozen…/spell_components.pdf