Most potting composts contain a combination of peat and vermiculite or perlite. Aggregates are generally "Sphagnum" (peat moss), sand, and perlite or vermiculite. It is sometimes mixed with lightweight aggregates, such as perlite or vermiculite. A common medium used is 'peat-lite', a mixture of peat moss, vermiculite, and perlite. Water glass is a useful binder of solids, such as vermiculite and perlite. Some vermiculite exfoliators blend with lower-cost perlite also. Plants are grown in sand, perlite, coconut coir and rockwool. Soil&colon; Use an ordinary commercial potting mix with 1/8 to 1/4 perlite mixed in. Like perlite, pumice is a lightweight, mined volcanic rock that finds application in hydroponics. Typical mixes include large-grade drainage material such as perlite, pumice, or ceramic balls. Magnesite, fire clay, gypsum, manganese, diatomite, marble, rock salt and perlite are also present. Common media include diatomaceous earth and perlite. There are important quantities of limestone, gypsum, baryte, perlite, feldspar, granite, etc. Deposits of perlite and pumice on Gyali provide much of the wealth of the island. The drum is pre-coated with a filter aid, typically of diatomaceous earth (DE) or Perlite.