Except for a few layers of top soils on the surface, much of the Earth is made up of solid materials called rocks. These soils and rocks are products of minerals: the basic units of rocks. ..........

Over 90% of gemstones are refined from naturally occurring minerals, formed via inorganic processes; the remaining 10% are organic gemstones, non-mineral material such as pearl, amber, coral and ..........

Gemstone-grade minerals are mineral crystals that have been artificially cut and refined into collectible items and precious jewelry. A mineral deemed worthy of gemstone quality must fulfill the ..........