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Stillwellite-(Ce) crystal
Marcelle Weber sp.
Photo by Violet Anderson
© Royal Ontario Museum
Stillwellite-(Ce) crystals
© Doug Merson
Stillwellite-(Ce) crystals
© Doug Merson
(Ce,La,Th,Ca)BSiO
Stillwellite-(Ce) is a rare mineral at MSH. It is difficult to recognize because of its crystal size and color.
PHYSICAL CHARACTERISTICS:
Color is usually pale pink.
Luster is vitreous to dull.
Diaphaneity is transparent to opaque.
Crystal System is hexagonal;
Crystal Habits include sharp hexagonal crystals terminated by
rhombohedra.
Cleavage not known.
Fracture is conchoidal.
Hardness is 5.5 – 6.5
Specific Gravity is approximately 4.65 g/cm
Streak is white.
Associated Minerals include aegirine, albite, amphibole group,
ancylite, apophyllite series, calcite, microcline, rinkite (mosandrite),
steacyite and titanite.
Distinguishing Features: Crystal habit, color and luster.
Origin: Named in 1955 after Frank Leslie Stillwell (1888-1963),
Austrian ore mineralogist.
CLASSIFICATION:
Dana System
# 54.2.3.2
Strunz Classification
# VIII/E.5-20
REFERENCES:
MinRec 21:341 (1990), Dana 8:1129 (1997)
DISTRIBUTION AND RARITY AT MONT SAINT-HILAIRE:
MSH
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