FUCHSITE, the green variety of muscovite

VARIETY INFORMATION:

  • VARIETY OF: Muscovite , KAl2(AlSi3O10)(F, OH)2, Potassium aluminum silicate hydroxide fluoride.
  • USES: mineral specimen and ornamental stone.
  • COLOR: emerald green.
  • HARDNESS: 2 - 3
  • CLEAVAGE: perfect in one direction, forming sheets.
  • CRYSTAL SYSTEM: monoclinic
  • Specimens

Fuchsite is a dark green variety of muscovite. It can have a wonderfully dark emerald green color that can have a beautiful sparkly shine if the crystals are small. It is often found in compact masses with small crystals. The green color is the result of chromium impurities.

PHYSICAL CHARACTERISTICS:

  • Color is green, often a deep green with a hint of yellow.
  • Luster is vitreous to pearly.
  • Transparency crystals are transparent to translucent.
  • Crystal System is monoclinic; 2/m
  • Crystal Habits include tabular crystals with a prominent pinacoid termination. Fuchshite's four prism faces form diamond shaped "books" and if modified by another pinacoid they form pseudo-hexagonal crystal "books". The sides of the crystal often tend to tapper. Also as lamellar rock forming masses and small flakes in detrital material. Twinned crystals can form flat five pointed stars.
  • Cleavage is perfect in one direction producing thin sheets or flakes.
  • Fracture is not readily observed due to cleavage but is uneven.
  • Hardness is 2 - 2.5.
  • Specific Gravity is approximately 2.8 (average)
  • Streak is white.
  • Associated Minerals are quartz, feldspars, beryl and tourmalines.
  • Other Characteristics: cleavage sheets are flexible and elastic, meaning they can be bent and will flex back to original shape.
  • Notable Occurrences include Sweden, Austria, Brazil and many USA localities.
  • Best Field Indicators are crystal habit, cleavage, elastic sheets, color and associations.
FUCHSITE specimens:
(hover for more info)
FUCHSITE specimen fuc-1
$ 10.00
Dims: 4" x 1-3/4" x 2"
Wt: 5.3 oz
Minas Gerais, Brazil
This specimen is likely composed of pure Fuchsite; it has all of the properties of mica, with the exception of its deep, chromium-induced green color. It is quite pretty, though not having any definite crystal form. The "book" is quite warped, and small portions have been folded a bit. However, on one area of the piece there seems to be some aventurine quartz hiding among the Fuchsite folds- the stuff scratched the steel casing of Steve's loupe! Funky!
no photo
fuc-1 ($ 10.00)
Minas Gerais, Brazil
FUCHSITE specimen fuc-2
$ 10.00
Dims: 3-1/2" x 1-3/4" x 1"
Wt: 4.5 oz
Minas Gerais, Brazil
If you're looking for a largish "book" of green, pearly-looking Fuchsite mica that is somewhat warped with no hexagonal form, you've come to the right place! This specimen is composed entirely of the chromium-tinted mineral. It's a good specimen if you don't have any, or for a younger collector who really likes mica and its forms.
no photo
fuc-2 ($ 10.00)
Minas Gerais, Brazil
FUCHSITE specimen fuc-3
$ 30.00
Dims: 4.3x2.8x1.2" (11.0x7.0x3.0 cm)
Wt: 10.4 oz. (294g)
Red Mountain, San Bernadino County, California, USA
This nodule of fuchsite is pale and impure on the outside, but a very pretty and deep green on the inside. The interior is perfect for fuchsite, with a myriad tiny crystals that are individually transparent and very lustrous. Fuschite specimens tend to be massive and flaky, but I find this one to be much more interesting and appealing.
no photo
fuc-3 ($ 30.00)
Red Mountain, San Bernadino County, California, USA
FUCHSITE specimen fuc-4
$ 25.00
dims mm=78.03x69.16x37.65
wt g=203
Taos County, New Mexico, USA
The flat side of this huynk of fuchsite is rather weathered and rusty looking. The larger part is a rather pretty deep blue-green, with a pearly luster. The crystals (sheets of mica) are not well formed, but they are well-aligned, so they all tend to reflect light at the same angle.
no photo
fuc-4 ($ 25.00)
Taos County, New Mexico, USA

 


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