Selenite Gem Guide and Properties Chart

Selenite is the name for transparent, colorless to near colorless crystals of gypsum, a hydrous calcium sulfate that is found in a number of forms. The name "selenite" comes from the Greek word selene, meaning "moon", no doubt in reference to the gem's white glow. Gypsum, in all varieties, is very soft and has perfect cleavage so it should be handled with care.

General Information

Classification
Optical Properties
Characteristic Physical Properties
Chemistry & Crystallography

Common Name

Selenite

Species

Gypsum

Transparency

Translucent

Dispersion

Strength: Strong Fire

Refractive Index

1.520-1.529
Tolerance:(+0.001/-0.001)

Birefringence

0.009-0.01

Optic Character

Biaxial

Optic Sign

Positive

Polariscope Reaction

Aggregate (AGG), Doubly Refractive (DR)

Fluorescence

SWUV: Inert to weak brownish white or greenish white
LWUV: Inert to weak brownish white or greenish white

CCF Reaction

None

Pleochroism

None

Hardness

1.5-2

Streak

White

Specific Gravity

2.250-2.350 Typical:2.300

Toughness

Poor

Luster

Waxy, Pearly, Vitreous, Subvitreous

Stability

Fair

Fracture

Granular

Cleavage

Perfect, in one direction, Good, in two directions

Chemical Name

hydrous calcium sulfate

Chemical Formula

CaSO₄-₂H₂O

Crystal System

Monoclinic

Chemistry Classification

Sulfate

Selenite Colors

Green
White
Colorless
Yellow
Blue
Brown
Pink
Gray
Black

Countries of Origin

Canada; United States of America (the); Morocco; Unknown; Brazil; Mexico; Madagascar; Australia; Spain

Care

Due to its soft nature selenite needs to be kept away from harder materials that will damage its surface. Selenite will turn cloudy if exposed to heat.