CaMg(CO₃)₂

Dolomite is common at MSH. Its hexagonal crystals display some interesting color zoning, with alternating colorless and yellow or light and dark brown zones.

PHYSICAL CHARACTERISTICS:

Color ranges from white to pale pink to beige brown, pale to
apple-green and colorless.
Luster is vitreous to pearly.
Diaphaneity is translucent to opaque.
Crystal System is hexagonal; R3.
Crystal Habits include sharp curved rhombohedra or as zoned
short hexagonal prisms and plates to 12mm.
Cleavage {1011} is perfect.
Fracture is conchoidal.
Hardness is 3.5-4
Specific Gravity is approximately 2.85 g/cm³.
Streak is colorless to white, grayish and greenish.
Associated Minerals include albite, anatase, calcite, chlorite group,
fluorapatite, fluorite, galena, gmelinite, marcasite, molybdenite,
pyrite, quartz, rutile, siderite and sphalerite.
Distinguishing Features: Crystal habit.
Origin: Named in 1791 after Déodat Guy Silvain Tancrède Gratet
de Dolomieu (1750-1801), French engineer and mineralogist.

CLASSIFICATION:

REFERENCES:
MinRec 21:305 (1990), Dana 8:450-451 (1997)

DISTRIBUTION AND RARITY AT MONT SAINT-HILAIRE:

MSH     PE     AP     MX     SS     MC     HF     BR     SX     FR
¤¤¤       —       —       —         —       —       ¤¤        —         —       — 

Legend