Minerals, Crystals, and Gems Our Earth’s crust consists of an aggregate of Minerals from the basic material in the star dust that formed our solar system and planets. Any Mineral allowed to develop unhindered will form a three dimensional shape called a Crystal. If a Crystal satisfies these three requirements: beauty, durability and rarity it is classified as a Gemstone. Crystals grow or enlarge by a process similar to that of a Pearl. Pearls grow from a single grain of sand,