Mckelveyite-(Y)

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Mckelveyite-(Y) crystals - click for larger pic
Mckelveyite crystal
Photo by Violet Anderson
© Royal Ontario Museum

Mckelveyite-(Y) crystals - click for larger pic
Mckelveyite-(Y) crystals
© Doug Merson

Mckelveyite-(Y) crystals - click for larger pic
Mckelveyite-(Y) crystals
© Doug Merson

(Ba,Sr)(Na,Ca,Y,REE)(CO · 3-5H

The occurrence of mckelveyite-(Y) is extremely rare at Mont Saint-Hilaire. It is difficult to distinguish from donnayite and ewaldite with which it often occurs in epitactic intergrowths.

PHYSICAL CHARACTERISTICS:

Color is usually yellow, orange-yellow to brown; greenish brown
to gray on spherical aggregates.
Luster is vitreous; resinous or greasy on fractures.
Diaphaneity is transparent to translucent.
Crystal System is triclinic; 1.
Crystal Habits include complex rounded hemimorphic crystals
and spherical aggregates.
Cleavage none.
Fracture is uneven.
Hardness is 3.5 – 4.
Specific Gravity is approximately 3.47 g/cm
Streak is white.
Associated Minerals include calcite, chlorite group, donnayite,
ewaldite, microcline and natrolite.
Distinguishing Features: Crystal habit.
Origin: Named in 1965 after Vincent Ellis, McKelvey (b. 1916),
Director, U.S. Geological Survey.

CLASSIFICATION:

Dana System
# 15.3.4.2

Strunz Classification
# V/D.04-20

REFERENCES:
MinRec 21:321-322 (1990), Dana 8:469-470 (1997)

DISTRIBUTION AND RARITY AT MONT SAINT-HILAIRE:

MSH
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Legend

Mckelveyite-(Y) crystals - click for larger pic
Mckelveyite-(Y) crystals
© Modris Baum

Mckelveyite-(Y) crystals - click for larger pic
Mckelveyite-(Y) crystals
© Jason B. Smith

Mckelveyite-(Y) crystals - click for larger pic
Mckelveyite-(Y) crystals
© Stephan Wolfsried