Over 90% of the Earth's crust is made up of silicates.
The rest of the minerals are lumped into a group called non-silicates.
The Earth is made up of thousands of different minerals.
What is the difference between a mineral and a rock?
Unlike most other gem materials, lapis lazuli is not a mineral.
Instead, it is a rock composed of multiple minerals.
The blue color of lapis lazuli is mainly derived from the presence of lazurite, a blue silicate mineral of the sodalite group with a chemical composition of (Na, Ca) Lapis Lazuli - The Rock: This photo shows a specimen of marble in which small patches of lazurite and abundant crystals of pyrite have formed.
The large cabochon on the top right has a few thin veins of calcite and some calcite mottling.
This stone is attractive and some people might prefer it, but the calcite reduces its desirability for most people.