(Th,U,Ce)(SiO1-x(OH)4x
Thorogummite is very rare at Mont Saint-Hilaire.
PHYSICAL CHARACTERISTICS:
Color ranges from pale brown to greenish brown and red-brown.
Luster is resinous.
Diaphaneity is translucent to opaque.
Crystal System is tetragonal; amd
Crystal Habits include radiating acicular crystals to 3mm and
embedded grains.
Cleavage {100} is distinct, not always apparent.
Fracture is conchoidal to splintery.
Hardness is 4.5
Specific Gravity is approximately 3 – 5 g/cm (depending on
water content).
Streak is brownish.
Associated Minerals include aegirine, analcime, astrophyllite,
catapleiite, eudialyte, gonnardite, microcline, rhodochrosite,
sérandite and sodalite.
Distinguishing Features: Crystal habit and color.
Origin: Named in 1889 for its thorium content and the Latin gummi
gum, alluding to its gum-like appearance.
CLASSIFICATION:
Dana System
# 51.5.2.5
Strunz Classification
# VIII/A.09-50
REFERENCES:
MinRec 21:343 (1990), Dana 8:1058-1059 (1997)
DISTRIBUTION AND RARITY AT MONT SAINT-HILAIRE:
MSH
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