Giant and perfectly idiomorphic crystal clusters of transparent
iceland spar type calcite occur in the Hejiawan mountain land in
southwestern Guizhou, China. The crystals were discovered since
1990 in a karstified limestone area.
Large "geodes" up to 60 m long occur in the otherwise barren limestone, which
are filled with crystals of iceland spar calcite up to 25 tons or a dimension of
3 x 2 x 1,5 m. Apart from some single crystals most crystals occur as distinctive
clusters of three or more indivdual crystals, forming giant crystal aggregates.
Detailed investigations show, that the calcite crystals are a product of hydrothermal activity
by low shallow seated and low temperature thermal fluids.
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We have to apologize for the bad quality of the images, but thats how they appear in the original publication. If you know of better photos of this fascinating locality, please let us know.
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The Hejiawan Iceland spar in a nutshell :
Mineralogy : |
Iceland Spar calcite |
Crystal Size : |
The largest crystal reaches 25 tons, which equals a dimension
of roughly 3 x 2 x 1,5 m. |
Geology & Formation |
Several decameter large "geodes" in karstified limestone, which are
filled with giant calcite crystal clusters of perfect idiomorphism. The crystals
have been formed by low temperature hydrothermal fluids.
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Current status : |
Apparently actively mined / quarried since 1990. Protection needed |
Remarks : |
More information needed
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Other notable & famous calcite occurences :
- More information about giant Iceland spar occurences can be found here (New Mexiko, USA), here (Helgustadir, Iceland) and here (Garibaldi mine, Australia)
- Another remarkable Iceland spar deposit with crystals up to 0,7 x 0,5 cm occur in basalt from Nizhnyaya, Krasnoyarsk kray Siberia, GUS.
- Sharp yellow scalenohedral crystals up to 1 m occur with galena and sphalerite in the famous Tri State District, Oklahoma / Missouri / Kansas, USA.
- For more information about calcite pseudomorphs after giant ikaite crystals and crystal aggregates please look here and here.
- Large to giant crystals of calcite up to 1 x 1 m size from metamorphic marbles have been reported from Sterlingbush, New York, USA.
- As calcite is one of the most common minerals, there are certainly other remarkable giant crystal occurences not listed here.
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Single crystal of iceland spar, Hejiawan
Photo source : Zhaochang, S. (1994) see literature below
Schematic sketch of a large geode containing iceland spar crystals, Hejiawan
Photo source : Zhaochang, S. (1994) see literature below
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Resources and relevant weblinks :
There is a fairly extensive publication about the occurence in
chinese language with a short english summary :
ZHAOCHANG, S. (1994): Gigantic and Supergigantic Crystal Clusters of Iceland-Spar Calcite, Mechanism
of Formation; in : Carsologica Sinica, Vol. 13, No. 4, pp. 383 - 394
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