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Marcasite crystals
© Doug Merson
Marcasite crystals
© Modris Baum
Marcasite crystals
© Bill Lechner
FeS
Marcasite is found rarely at MSH, it occurs in narrow fracture cavities and fissures in hornfels, or in nepheline syenite close to hornfels contact.
PHYSICAL CHARACTERISTICS:
Color is usually pale brass-yellow.
Luster is metallic.
Diaphaneity is opaque.
Crystal System is orthorhombic; Pnnm
Crystal Habits include thin bladed single crystals to 2-3mm
and oriented crystal groups.
Cleavage {101} is distinct.
Fracture is uneven.
Hardness is 6 – 6.5.
Specific Gravity is approximately 4.9 g/cm
Streak is gray to black.
Associated Minerals include Albite, analcime, calcite, dawsonite,
fluorite, ilmenite, magnesite, muscovite, pyrite, pyrrhotite and quartz.
Distinguishing Features: crystal habit and forms.
Origin: Named in 1845 from the Assyrian markhashitu, related
to the Arabic markhashi, an old province thought to be located
in the northeastern part of Persia.
CLASSIFICATION:
Dana System
# 2.12.2.1
Strunz Classification
# II/D.20-10
REFERENCES:
MinRec 21:321 (1990), Dana 8:120-121 (1997)
DISTRIBUTION AND RARITY AT MONT SAINT-HILAIRE:
MSH
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Marcasite crystals
© Modris Baum