Chloroxiphite

Chloroxiphite
Chloroxiphite
Photograph of a mendipite sample with a dark crystal of chloroxiphite embedded in it and a smaller, bright blue diaboleite crystal at the chloroxiphite's top edge.
Chloroxiphite crystal (dark green) embedded in mendipite. The bright blue material is diaboleite.
General
Category Halide
Chemical formula Pb3CuO2Cl2(OH)2
Strunz classification 03.DB.30
Crystal symmetry 2/m - Prismatic
Unit cell

a = 6.6972(8) Å, b = 5.7538(5) Å, c = 10.4686(14) Å

β = 97.747(10)°
Identification
Color Dull olive green
Crystal system Monoclinic
Cleavage On {_101} perfect; {100} distinct
Tenacity Very brittle
Mohs scale hardness 2½
Luster Adamantine, resinous
Streak Light green yellow
Specific gravity 6.76 - 6.93
Optical properties Biaxial (-)
Refractive index nα = 2.160 nβ = 2.240 nγ = 2.250
Birefringence δ = 0.090
Pleochroism Visible
2V angle Measured: 70° , Calculated: 36°
References [1][2][3]

Chloroxiphite (Greek: χλωρός, green; ζιφος, blade) is an olive green to black halide mineral sometimes found in the Mendip Hills, Somerset, England associated with mendipite. Like mendipite it is an oxychloride mineral and formed from the alteration of lead ore (galena) by a prehistoric sea.

It is rare but can be found in most of the quarries with manganese pods pyrolusite in the Mendips.[citation needed] It is found in mendipite, but it is not hard to distinguish as mendipite is white or pink. Its name comes from the Greek words meaning "green", describing its color, and "blade" as its crystal form is long blade-like crystals that often show the growth pattern and time taken to form.

References

  1. ^ Mindat.org
  2. ^ Webmineral.com
  3. ^ Handbook of Mineralogy
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