For sand, the best source is from inland quarries and river sand. River sand is no good for internal use because erosion has caused there to be no sharp edges.
Good sand should have small, medium and large grains in it.
Sand should never have leaves or iron in it. If it does, it will affect the finish. It can have clay in it but if there is too much, it can make the setting of the cement take longer.
Expanded perlite is used in lightweight aggregate mixes along with gypsum plaster or Portland cement. It is a volcanic rock that has a small amount of water in it.
It will then be crushed until it is the right size and softened by using a small amount of heat. Once it has softened, even more heat is added to make it bigger. It gets bigger because the water inside creates steam.
Vermiculite
Granulated Pumice is a rock from a volcano. It is used for acoustic plaster mixes because it can help to block sounds.
Granite chippings are used in granolithic work like floors or paths because it is hard wearing. The chippings are made of crushed granite.
Carborundum chippings are made from silica and carbon mixed in granolithic work.
Pebble dashing materials are made of stones such as white limestone spar and dorset spar.