Regenbogen Mondstein Labradorit Cabochon Rainbow Moonstone Labradorite Gemstone

Unverkauft Siehe ähnliche Artikel EUR 25,60 Sofort-Kaufen, Kostenloser Versand, eBay-Käuferschutz
Verkäufer: classicrocksandgems2 ✉️ (5.419) 100%, Artikelstandort: Morsbach, DE, Versand nach: WORLDWIDE, Artikelnummer: 161125212098 Regenbogen Mondstein Labradorit Cabochon Rainbow Moonstone Labradorite Gemstone. Top Rainbow Moonstone Cabochon - India Actually a clear labradorite but commercial known as rainbow moonstone A blue shimmer runs over the stone when moved in direct light kindly note that pictures are taken on a black surface to accentuate the blue shimmer Class : Orthoclase     Mohs Hardness: 6.5-7     Weight: 4.25ct        Size:12.2x10x5.5mm

Orthoclase
General
CategorySilicate mineral
Formula (repeating unit) KAlSi3O8
Identification
ColorColorless, Greenish, Greyish yellow, White, Pink
Crystal habit Can be anhedral  or euhedral . Grains are commonly elongate with a tabular appearance.
Crystal system Monoclinic  (2/m) space group  C2/m
Twinning Typically displays carlsbad twinning. Baveno and manebach twins have also been reported in orthoclase.
Cleavage Has perfect cleavage on {001} and good cleavage on {010}. Cleavages intersect at 90°. It can be difficult to see cleavage in thin section due to orthoclase's low relief.
Mohs scale hardness6 (defining mineral)
Luster Vitreous, pearly on cleavage surfaces
Streak white
Diaphaneity Transparent to translucent
Specific gravity 2.55–2.63
Optical propertiesBiaxial (-), 2V = 65–75
Refractive index nα = 1.518–1.520 nβ = 1.522–1.524 nγ = 1.522–1.525
Birefringence 0.0050–0.0060
Dispersion relatively strong
Extinctionparallel to cleavage
Diagnostic featuresDistinguishable from microcline by a lack in gridiron twinning. Distinguishable from sanidine by a larger 2Vx.
Other characteristicsLow negative relief
References[1] [2] [3]

Orthoclase  (endmember formula K Al Si 3O 8) is an important tectosilicate  mineral  which forms igneous rock . The name is from the Greek  for "straight fracture," because its two cleavage planes are at right angles to each other. Alternate names are alkali feldspar , potassium feldspar  and K-feldspar . The gem known asmoonstone  (see below) is largely composed of orthoclase.

Contents   [hide ] 
  • 1  Formation and subtypes
  • 2  Uses
  • 3  See also
  • 4  References

Formation and subtypes [ edit ]

Orthoclase is a common constituent of most granites  and other felsic  igneous rocks  and often forms huge crystals and masses in pegmatite .

Typically, the pure potassium endmember of orthoclase forms a solid solution  with albite , the sodium endmember (NaAlSi3O8), of plagioclase . While slowly cooling within the earth, sodium-rich albite lamellae form by exsolution , enriching the remaining orthoclase with potassium. The resulting intergrowth of the two feldspars is called perthite .

Adularia with pyrite  incrustations.

The higher-temperature polymorph  of orthoclase is sanidine . Sanidine is common in rapidly cooled volcanic rocks such asobsidian  and felsic pyroclastic  rocks, and is notably found intrachytes  of the Drachenfels , Germany . The lower-temperature polymorph of orthoclase is microcline . Adularia is found in low temperature hydrothermal  deposits, in the Adula Alps  ofSwitzerland . The largest documented single crystal of orthoclase was found in Ural mountains , Russia . It measured ~10×10×0.4 m and weighed ~100 tons.[4]

Uses [ edit ]

Together with the other potassium feldspars  orthoclase is a common raw material for the manufacture of someglasses , some ceramics , such as porcelain , and as a constituent of scouring powder.

Some intergrowths of orthoclase and albite  have an attractive pale luster  and are called moonstone  when used in jewellery. Most moonstones are translucent and white, although grey and peach-coloured varieties also occur. In gemology, their luster is called adularescence  and is typically described as creamy or silvery white with a "billowy" quality. It is the state gem  of Florida .

The gemstone commonly called rainbow moonstone  is more properly a colourless form of labradorite  and can be distinguished from "true" moonstone by its greater transparency and play of colour, although their value and durability do not greatly differ.

Orthoclase is one of the ten defining minerals of the Mohs scale of mineral hardness .

See also [ edit ]
  • List of minerals

References [ edit ]
  1. Jump up ^  Mindat
  2. Jump up ^  Handbook of Mineralogy
  3. Jump up ^  Webmineral
  4. Jump up ^  P. C. Rickwood (1981). "The largest crystals" . American Mineralogist  66 : 885–907.
Categories : 
  • Potassium minerals
  • Aluminium minerals
  • Tectosilicates

  • Condition: Neu: Sonstige (siehe Artikelbeschreibung)
  • Stein: Rainbow Moonstone
  • Farbe: Blue Shimmer
  • Schliff: Cabochon
  • Reinheit: VS
  • Gewicht: 4.25 ct
  • Regenbogen Mondstein Labradori: Rainbow Moonstone Labradorite Gemstone
  • Pietra di luna arcobaleno: Pierre de lune arcanciel

PicClick Insights - Regenbogen Mondstein Labradorit Cabochon Rainbow Moonstone Labradorite Gemstone PicClick Exklusiv

  •  Popularität - 6 Beobachter, 0.0 neue Beobachter pro Tag, 2.855 days for sale on eBay. Super hohe beobachtend. 0 verkauft, 1 verfügbar.
  •  Bestpreis -
  •  Verkäufer - 5.419+ artikel verkauft. 0% negativ bewertungen. Großer Verkäufer mit sehr gutem positivem Rückgespräch und über 50 Bewertungen.

Die Leute Mochten Auch PicClick Exklusiv