Thumbnails
Gypsum crystal
Quintin Wight sp.
Photo by Violet Anderson
© Royal Ontario Museum
Gypsum crystals
© Doug Merson
Gypsum crystals
© Doug Merson
CaSO · 2H
The occurrence of gypsum at MSH is rare.
PHYSICAL CHARACTERISTICS:
Color is usually colorless or white.
Luster is vitreous; silky on cleavages.
Diaphaneity is transparent.
Crystal System is monoclinic; 2/
Crystal Habits include sharp, thin elongated prisms and blades
to 5mm and drusy microcrystals.
Cleavage {010} is perfect, {100} and {011} are distinct.
Fracture is splintery.
Hardness is 2.
Specific Gravity is approximately 2.3 g/cm
Streak is white.
Associated Minerals include mica group and natrolite.
Distinguishing Features: Crystal habit and color.
Origin: Known from antiquity, its name come from the Greek
gypsos, plaster, alluding to its principal use.
CLASSIFICATION:
Dana System
# 29.6.3.1
Strunz Classification
# VI/C.22-20
REFERENCES:
MinRec 21:325 (1990), Dana 8:598-601 (1997)
DISTRIBUTION AND RARITY AT MONT SAINT-HILAIRE:
MSH
¤¤¤
Gypsum crystals
© Modris Baum