Diamond Vs. Alexandrite

Chemical composition

• Alexandrite is a variety of chrysoberyl (BeAl2O4), but with iron, titanium and chromium inclusions. Vanadium may also be an inclusion.

  Diamonds are made of pure carbon (C) and come in a range of colors depending on the chemical inclusion.

Color

• Diamonds are known for their fire (sparkling flashes of colors) and come in a variety of colors depending on the chemical inclusion. They are the same color in natural and artificial light.

  There is only one type of alexandrite, which is red in artificial light and green in natural light.

History

• Diamonds have been known of since ancient times, but alexandrite was discovered in April 1834.

Function

• Both diamonds and alexandrites are used for jewelry, and diamonds are a birthstone for April while alexandrites are a birthstone for June.

  Diamonds are also used for industrial purposes such as abrasives and in gem cutting.

Hardness and Crystal System

• The hardness of gemstones is rated on a relative scale of hardness called the Moh's scale. Diamonds rate a 10 on the Moh's scale while alexandrite rates an 8.5.

  The crystal system for diamond is isometric (in the subcategory of hexoctahedral) while the crystal system for alexandrite is orthorhombic (in the subcategory of dipyramidal).