Natural Alexandrite is formed by nature and mined and cut by man. Alexandrite are chemical minerals that formed over millions of years deep in the earth. The earth is divided into three segments: crust, mantle, and core. The crust is the top layer –about 5%; the mantle is the second, or middle layer-approximately 28%; and the deepest layer is the core –which is almost entirely composed of molten rock or lava. Gems are formed when molten lava is pushed through to the crust under extremely high pressure in very small quantities. During its travel to the surface through cracks and fissures in the mantle, it mixes with many different minerals in the specific areas it travels giving rise to different gemstones.
The time period between the molten lava leaving the core and pushing its way through the mantle and crust is anywhere from 2,000 million years to 3,000 million years.
Alexandrite and emerald form at a depth of approximately 250km. Diamonds form over 500km and have to push through to the surface without the intermingling of other minerals! Gem bearing rock called Pegmatite cuts through other rocks that act as catalysts and undergo chemical reactions in different stages forming alexandrite, crysoberyl, moonstone, emerald, zircon and different varieties of quartz. The chemicals that act as the catalyst in other rocks are primarily beryllium and aluminum. Alexandrite and emerald are almost always found in the same areas and may even be lustered together.
2008: Mining has produced varying quantities of Alexandrite found in schist.