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Andradite crystals - click for larger pic
Andradite crystal
W. Henderson specimen
Photo by Violet Anderson
©Royal Ontario Museum

Andradite crystals - click for larger pic
Andradite crystals
© Doug Merson

Andradite crystals - click for larger pic
Andradite crystals
© Gilles Haineault

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Home > Mineral Descriptions > Andradite - (3 Photos)



Andradite
Ca3Al2(SiO4)3

     Andradite, a member of the garnet group, occurs at MSH in miaroletic cavities and rarely in marble xenoliths.

PHYSICAL CHARACTERISTICS:

Color is usually dark to pale-olive green, brownish green and
    yellow-green.
Luster is vitreous.
Diaphaneity is translucent to opaque.
Crystal System is isometric; Ia3d.
Crystal Habits include sharp dodecahedra to 8mm and small
    clusters of crystals.
Cleavage: none observed.
Fracture is subconchoidal.
Hardness is 6.5 - 7.5
Specific Gravity is approximately 3.8 g/cm3.
Streak is white.
Associated Minerals include barite, grossular, pectolite and
    sodalite.
Distinguishing Features: Crystal habit and luster.
Origin: Named in 1868 for Jose Bonifacio d'Andrada e Silva
    (1763-1838), Brazilian statesman and geologist who first
    examined and described the mineral.

CLASSIFICATION:

Dana System
# 51.4.3b.1

Strunz Classification
# VIII/A.8-110

REFERENCES:
MinRec 21:296 (1990), Dana 8:1044-1046 (1997)

DISTRIBUTION AND RARITY AT MONT SAINT-HILAIRE:

MSH
¤¤¤

PE
--

AP
--

MX
¤¤

SS
--

MC
¤¤

HF
--

BR
--

SX
--

FR
--

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