polished-sunstone

SUNSTONE

Sunstone’s phenomenal varieties show a distinct and lively glitter called aventurescence.

ABOUT SUNSTONE

Sunstone is a member of the feldspar group. Both the orthoclase and the plagioclase feldspar species boast a sunstone variety. Other feldspar group gems include moonstone, non-phenomenal orthoclase, phenomenal and non-phenomenal labradorite, and amazonite. Sunstone from Oregon is gaining attention as a natural and untreated product of the United States.

FELDSPAR

Sunstone is a member of the feldspar group of minerals.


AVENTURESCENCE

Sunstone can have a sparkly, metallic-looking luster caused by flat, reflective inclusions.


OREGON

Oregon sunstone is a transparent feldspar with glittery copper inclusions.


FACTS

  • Mineral: Feldspar
  • Chemical composition: 
  • Orthoclase – KAlSi3O8
  • Oligoclase and labradorite – solid solution between NaAlSi3O8 and CaAl2Si2O8
  • Color: Yellow, green, red, red-brown, colorless
  • Refractive Index: 
  • Orthoclase sunstone – 1.518 to 1.526
  • Oligoclase sunstone – 1.537 to 1.547
  • Labradorite sunstone – 1.559 to 1.568
  • Birefringence: 
  • Orthoclase – 0.005 to 0.008
  • Oligoclase and labradorite – 0.007 to 0.010
  • Specific gravity: 
  • Orthoclase – 2.58
  • Oligoclase – 2.65
  • Labradorite – 2.70
  • Mohs hardness:  6.0 – 7.2

QUALITY FACTORS

The following factors combine to determine a sunstone’s value.

COLOR

The most in-demand sunstone colors are deep red – like this gem – deep green, and intense bicolors.

CLARITY

Small inclusions provide a reddish or golden sheen; larger inclusions create glittering reflections.

CUT

Creative cuts and calibrated gems alike are designed to highlight the gem’s glowing colors.

CARAT WEIGHT

Sunstone is available in a range of sizes, but large carved gems like this Oregon beauty are rare.

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