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Ewaldite crystals
Gary Glenn specimen
Photo by Violet Anderson
© Royal Ontario Museum
Ewaldite crystals
Photo by Violet Anderson
© Royal Ontario Museum
Ewaldite crystals
© Doug Merson
Ewaldite crystals
© Stephan Wolfsried
Ba(Ca,Y,Na,K)(CO
Ewaldite is relatively rare at Mont Saint-Hilaire. It is very difficult to distinguish from mckelveyite-(Y). The epitactic overgrowth of donnayite-(Y) should help with the identification. On most of the accompanying photos you will find a cap of donnayite-(Y).
PHYSICAL CHARACTERISTICS:
Color ranges from off-white, beige, yellow-brown, yellow-green,
greenish-gray to dark bluish gray.
Luster is greasy or dull.
Diaphaneity is opaque.
Crystal System is hexagonal; mc
Crystal Habits include sharp hexagonal hemimorphic crystals to
3mm, with some groups of crystals to 10mm.
Cleavage none observed.
Fracture is (??).
Hardness is 3.
Specific Gravity is approximately 3.25 g/cm
Streak is white.
Associated Minerals include aegirine, albite, analcime, ancylite,
apophyllite series, calcite, leucosphenite, molybdenite,
monteregianite, narsarsukite and quartz.
Distinguishing Features: Crystal habit.
Origin: Named in 1971 after Paul Peter Ewald (b. 1888), physicist
and crystallographer, Polytechnic Institute of New York, U.S.A.
CLASSIFICATION:
Dana System
# 14.2.4.1
Strunz Classification
# V/D.04-05
REFERENCES:
MinRec 21:309 (1990), Dana 8:453-454 (1997)
DISTRIBUTION AND RARITY AT MONT SAINT-HILAIRE:
MSH
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Ewaldite crystals
© Saul Krotki
Ewaldite crystals
© Stephan Wolfsried