Terlinguaite

Terlinguaite
Terlinguaite, collected from Mariposa Mine, Terlingua District, Brewster County, Texas, United States
General
Category	Halide mineral
Formula	Hg4+3Hg2+Cl2O2
IMA symbol	Tlg [1]
Strunz classification	3.DD.20
Crystal system	Monoclinic
Crystal class	Prismatic (2/m) (same H-M symbol)
Space group	C2/c
Unit cell	a = 19.51  Å, b = 5.91 Å c = 9.47 Å; β = 143.81°; Z = 4
Identification
Color	Sulfur-yellow, greenish yellow, brown
Crystal habit	Aggregates of equant to elongated crystals, powdery, massive
Cleavage	Perfect on [101]
Tenacity	Brittle
Mohs scale hardness	2.5
Luster	Brilliant adamantine
Streak	Lemon-yellow, turning olive-green
Diaphaneity	Transparent to translucent
Specific gravity	9.22
Optical properties	Biaxial (-)
Refractive index	nα = 2.350 nβ = 2.640 nγ = 2.660
Birefringence	δ = 0.310
Pleochroism	Weak, green and yellow
2V angle	Measured: 20°
Alters to	turns olive-green on exposure to light
References	[2] [3] [4]

Terlinguaite is the naturally occurring mineral with formula Hg4+3 Hg ²⁺ Cl ₂ O ₂. It is formed by the weathering of other mercury-containing minerals. It was discovered in 1900 in the Terlingua District of Brewster County, Texas, for which it is named. ^[5] Its color is yellow, greenish yellow, brown, or olive green.

References

1. Warr, L.N. (2021). "IMA–CNMNC approved mineral symbols". Mineralogical Magazine. 85 (3): 291–320. Bibcode:2021MinM...85..291W. doi: 10.1180/mgm.2021.43 . S2CID   235729616.
2. Handbook of Mineralogy
3. Mindat.org
4. Webmineral data
5. Hillebrand, W. F.; Schaller, W. T. (1907). "Art. XXVI. "The Mercury Minerals from Terlingua, Texas: Kleinite, Terlinguaite, Eglestonite, Montroydite, Calomel, Mercury"" . The American Journal of Science. s4-24 (139): 259–274. doi:10.2475/ajs.s4-24.141.259 . Retrieved 2009-05-21.