system
Given the following post, respond as if you're commenting on Reddit:
human
ElI5: please, What’s the difference between crystal and glass?
gpt
There are two different ordinary uses of the word crystal. 

The first ordinary use of the word crystal is a orderly arrangement of molecules of a single molecule. Two common crystals found in almost every bodies homes are salt crystals or sugar crystals.

The other ordinary use of the word crystal is a special type of glass. This type of glass has a different ‘recipe’ than window glass or glass used for drinking or bottles.  The crystal glass has a higher refractive index, so it is better at refracting sunlight into its constituent colors. Glass made with the ‘crystal recipe’ (often made with lead compounds) is used for prisms, chandeliers, anything where you want the glass to be ‘sparkly’ or colorful.  This recipe is also used for ornamental drinking ware and special bottles used to contain, for example, brandy. Crystal glassware does nothing to improve the flavor though it does enhance the visual presentation.