Description: The purple color in amethyst from most localities is unevenly distributed in the individual crystals. This variety of quartz owes its color to gamma irradiation (Berthelot, 1906) and the presence of traces of iron built into its crystal lattice (Holden, 1925). Amethyst can be faceted and is commonly used as a gem material in jewelry.

Color: Violet, purple

Streak: Colorless (harder than the streak plate)

Luster: Vitreous (glass-like) in crystals

Fracture: Conchoidal

Cleavage: None - typically breaks with a conchoidal fracture.

Hardness: 7 on Moh’s scale.

Density/Specific Gravity: 2.6 - 2.7 g/cm³

Distinguishing Physical Properties:

• Hardness: (easily scratches glass, also harder than steel)

• Luster: glass-like

• Fracture: conchoidal fracture in crystals, in massive specimens the fracture often looks irregular to the naked eye, but still conchoidal at high magnification.

• Cleavage: poor to indistinct cleavage