Vein of dark red montroydite and orange kleinite in a matrix of white calcite
General
Category
Oxide mineral
Formula (repeating unit)
HgO
IMA symbol
Mtyd[1]
Strunz classification
4.AC.15
Crystal system
Orthorhombic
Crystal class
Dipyramidal (mmm) H-M Symbol: (2/m 2/m 2/m)
Unit cell
a = 5.52 Å, b = 6.6 Å, c = 3.52 Å; Z=4
Identification
Color
Deep red, brownish red to brown
Crystal habit
Long prismatic, equant, rarely flattened; striated; massive to vermicular clusters
Cleavage
Perfect {010}
Tenacity
Sectile
Mohs scale hardness
1.5 - 2.0
Luster
Sub-adamantine, vitreous
Streak
Yellow brown
Diaphaneity
Transparent to translucent
Specific gravity
11.23
Optical properties
Biaxial (+)
Refractive index
nα = 2.370 nβ = 2.500 nγ = 2.650
Birefringence
δ = 0.280
Pleochroism
Deep red-orange to yellowish brown (visible in thick sections)
2V angle
Large
References
[2][3]
Montroydite is the mineral form of mercury(II) oxide with formula HgO. It is a rare mercury mineral. It was first described for an occurrence in the mercury deposit at Terlingua, Texas and named for Montroyd Sharp who was an owner of the deposit.[2]
Montroydite occurs in mercury deposits of hydrothermal origin. Associated minerals include: native mercury, cinnabar, metacinnabar, calomel, eglestonite, terlinguaite, mosesite, kleinite, edgarbaileyite, gypsum, calcite and dolomite.[3]
Montroydite is the mineral form of mercury(II) oxide with formula HgO. It is a rare mercury mineral. It was first described for an occurrence in the mercury...
Montroydite crystal structure (Aurivillius 1964) along the b axis. (Created with the help of the free structure program VESTA and the CIF data from Karin...
Minerals from Terlingua, Texas: Kleinite, Terlinguaite, Eglestonite, Montroydite, Calomel, Mercury"". The American Journal of Science. s4-24 (139): 259–274...
Minerals from Terlingua, Texas: Kleinite, Terlinguaite, Eglestonite, Montroydite, Calomel, Mercury". The American Journal of Science. s4-24 (139): 259–274...
order of abundance, are cinnabar, mercury, edgarbaileyite, metacinnabar, montroydite, eglestonite, calomel, an unidentified yellow massive cryptocrystalline...
any of the known locations of its origin. Mineral associations include montroydite, calcite, gypsum, and at some localities native mercury. Spinel twinning...
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