Inorganic Gemstones

Sunstone

Sunstone Beads

Oligoclase is really a types of plagioclase feldspar. The range utilized in jewellery is known as sunstone or, less commonly, aventurine feldspar. It's reflective inclusions of red, orange, or green platy crystals, which provide a metallic glitter. Sunstone might be faceted or carved - frequently cabochons.

Sunstone happens in metamorphic and igneous rocks in Norway, the United States, India, the first kind USSR, and Canada.


Properties
Chemical Composition: 
Aluminum silicate of potassium, sodium and calcium. KAlSi3O8. Isomorphous series made up of Albite (Na), Oligoclase, Andesine, Labradorite, Bytownite and Anorthite (Ca) where the two end member are NaAlSi3O8 and CaAl2Si2O8.
Classification / Type: 
-
Colors / Varieties: 
Plagioclase:
  • Albite: Moonstone (orthoclase-albite)
  • Labradorite: Transparent (white, grey, yellow); Phenomena: chatoyancy, asterism, play of color i.e., labradorescence); Spectrolite: dark background with play of color.
  • Oligoclase: Sunstone: Phenomena: aventurescent, chatoyancy
Crystal System / Forms: 
Triclinic System
Hardness: 
6.5
Specific Gravity: 
2.63 - 2.72
Cleavage / Fracture: 
Easy 2 directional / Uneven.
Optic Character: 
Anisotropic, D.R.; Biaxial negative
Lustre: 
Vitreous
Refractive Index / Birefringence: 
1.542 - 1.549 / 0.00
Pleochroism: 
Not common.
Dispersion: 
0.012
Magnification: 
Platelets of goethite, copper, hematite, fingerprints and crystal inclusions.
U.V. Fluorescence: 
Variable.
Spectrum: 
Not characteristic.
Cause of Color: 
Aventurescent effect due to reflections from metallic inclusion like hematite, goethite or copper.
Treatment (Enhancement): 
None.
Specific Tests & Remarks: 
-
Synthesis: 
None.
Simulants (with key separation tests): 
Sunstone simulated by aventurine quartz (structure), goldstone glass (inclusions).
Geological Occurrence: 
Igneous rocks, pegmatite.
Sources: 
U.S.A. (Oregon), India, Kenya, Norway, Russia.
Cuts & Uses: 
Facetted, cabochon, beads and carving.

Did you know?

Jewellery is one of the most bought products online. An estimated $1 billion USD of diamonds are bought annually via the Internet. Over 40 million people use the Internet to trade!

In Germany, the garland of ambers is hung around the necks of the infants, so that their teeth might come out without much trouble.

In Turkey, people fix a piece of amber in the hubble-bubble, dogged by an age old belief that the presence of the jewel would destroy all the germs and no disease would spread, even after many have dragged their puffs from it.

In Greece, people think if wine is poured into the cups made of amethyst, one does not get drunk after drinking that.

In Rome, a talisman having coral pieces is considered very auspicious to quell the bad spells of evil look. The Romans were in the habit of hanging chains made of ancient coral pieces from the cradle of the infants to protect them from evil effects.

In China, people wear rings studded with tiny conch or oyster shells as they believe it cures all aches such as stomach ache, worms and like.

In India, pendants made of silver and studded with pearls are hung from the necks of the children to save them from any bad effects.

Greeks still believe, if women wear blue sapphires then no sense of immorality would pollute their mind nor can any fear of the supernatural can trouble them.

The Pope Innocent III had circulated an order asking all the priests wear blue sapphire, so that morality can be strengthened.

It is said about turquoise, that when the stone changes its color into yellow, it actually signals bad times to the person who wears it.

It is believed that a turquoise gifted to a friend or a lover turns his or her life into one of happiness and good luck.

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