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Opal
SiO2 · nH2O

     Opal is extremely rare at Mont Saint-Hilaire.

PHYSICAL CHARACTERISTICS:

Color is usually colorless or white.
Luster is vitreous to dull, waxy or greasy.
Diaphaneity is transparent to opaque.
Crystal System is amorphous.
Crystal Habits include (??).
Cleavage is absent.
Fracture is conchoidal, uneven, irregular to splintery.
Hardness is 5.5 - 6.5
Specific Gravity is approximately 2.1 g/cm3.
Streak is white.
Associated Minerals include (??).
Distinguishing Features: Crystal habit.
Origin: Known from Antiquity and named from the Greek opalios,
   or Sanskrit, upala, opal.

CLASSIFICATION:

Dana System
# 75.2.1.1

Strunz Classification
# IV/D.01-80

REFERENCES:
Dana 8:1587-1592 (1997)

DISTRIBUTION AND RARITY AT MONT SAINT-HILAIRE:

MSH
¤¤¤

PE
--

AP
--

MX
--

SS
--

MC
--

HF
--

BR
--

SX
--

FR
--

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