Chlorophane

Where it forms, where it's found

Geological setting: Rare-element pegmatites and hypothermal mineral veins.

25recorded occurrences

Source · OpenStreetMap

Physical

Hardness: 1Talc
2Gypsum
3Calcite
4Fluorite
5Apatite
6Orthoclase
7Quartz
8Topaz
9Corundum
10Diamond
Transparency: Transparent · Translucent
Colour: Reddish pink · red · red-brown · purple · green · smoky · colorless
Color fades upon prolonged exposure to light.
Streak: white
Cleavage: Perfect
Perfect on (111)
Fracture: Sub-Conchoidal

Optical

UV response: Grey-green, green to blue-green short-wave and medium-wave and afterglow, violet long-wave fluorescence (NOTE: prolonged exposure to light changes the green fluorescence to the same violet as shown under long-wave.)

Isotropy testPPL ↔ XPL diagnostic

PPL intrinsic colour; no change on stage rotation

XPL extinct at every orientation

Crystallography

Crystal system: Isometric
Morphology: Typically massive. Octahedral microcrystals and cubic macrocrystals are very rare.

Chemical composition

Constituent elements: Mass composition breakdown
Element Atoms At. mass g/mol Mass g/mol Mass share
20CaCalcium Calcium 1 40.078 40.078
51.33%
9FFluorine Fluorine 2 18.998 37.996
48.67%
Total 78.074 100.00%
Mass share = atoms × atomic mass ÷ molar mass × 100
From Mindat formula

Mass composition breakdown
Element	Atoms	At. mass g/mol	Mass g/mol	Mass share
20CaCalcium	Calcium	1	40.078	40.078	51.33%
9FFluorine	Fluorine	2	18.998	37.996	48.67%
	Total	78.074	100.00%

Synonyms

Cobra Stone
Pyroemerald
Pyrosmaragd

Literature, links & citation

Citations

1794De Grotthaus. In: Delamétherie (1794), Journal Phys.: 45: 398.
1951Palache, Charles; Berman, Harry; Frondel, Clifford (1951) The System of Mineralogy (7th ed.) Vol. 2 - Halides, Nitrates, Borates, Carbonates, Sulfates, Phosphates, Arsenates, Tungstates, Molybdates, Etc. John Wiley and Sons.
1994Robbins, Manuel (1994) Fluorescence - Gems and Minerals under Ultraviolet Light. Geoscience Press, Inc.

Cite this entry

@misc{mineral2026,
  author    = {Mineral Index editorial board},
  title     = {Chlorophane — Mineral Index},
  year      = {2026},
  url       = {https://mineralindex.org/minerals/chlorophane-948},
  note      = {Accessed 2026-05-11}
}