Gypsum - Mineral Properties and Uses |
|
|
What is Gypsum? |
Gypsum is an evaporite mineral most commonly found in layered sedimentary deposits in association with halite, anhydrite, sulfur, calcite and dolomite. Gypsum (CaSO4.2H2O) is very similar to Anhydrite (CaSO4). The chemical difference is that gypsum contains two waters and anhydrite is without water. Gypsum is the most common sulfate mineral. |
Uses |
Gypsum uses include: manufacture of wallboard, cement, plaster of Paris, soil conditioning, a hardening retarder in Portland cement. Varieties of gypsum known as "satin spar" and "alabaster" are used for a variety of ornamental purposes, however their low hardness limits their durability. |
Color |
clear, colorless, white, gray, yellow, red, brown |
Streak |
white |
Luster |
vitreous |
Diaphaneity |
transparent to translucent |
Cleavage |
perfect |
Hardness |
2 |
Specific Gravity |
2.3 |
Distinguishing
Characteristics |
cleavage, specific gravity, low hardness |
Crystal System |
monoclinic |
Chemical Classification |
sulfate |
Chemical Composition |
hydrous calcium sulfate, CaSO4.2H2O |
|
|
 |
Satin spar, a fibrous variety of gypsum from Derbyshire, England.
Specimen is approximately 4 inches (10 centimeters) across.
|
 |
Gypsum from Grand Rapids, Michigan.
Specimen is approximately 4 inches (10 centimeters) across.
|
 |
Selenite, a variety of gypsum from Penfield, New York.
Specimen is approximately 2-1/2 inches (6.4 centimeters) across.
|
 |
Selenite, a variety of gypsum from Penfield, New York.
Specimen is approximately 2-1/2 inches (6.4 centimeters) across.
|
 |
Gypsum from North Holston, Virginia.
Specimen is approximately 1-1/2 inches (3.8 centimeters) across.
|
 |
Satin spar, a fibrous variety of gypsum from Derbyshire, England.
Specimen is approximately 3 inches (7.6 centimeters) across.
|
 |
Alabaster, a variety of gypsum, from Pomaia, Italy.
Specimen is approximately 3 inches (7.6 centimeters) across.
|
 |
The translucent characteristic of alabaster, a variety of gypsum, from Pomaia, Italy.
Specimen is approximately 3 inches (7.6 centimeters) across.
|
More Information About Minerals!
Mineral photographs that appear on this page with a Geology.com copyright mark are property of Geology.com and may not be used beyond our website. If you like these photos and would like to share them with others please link to this page or email its URL. The photos were taken and composed by Ann Bryant.
|
|
