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SUNSTONE

Introduction:  Sunstone is a variety of the species labradorite (or sometimes oligoclase).  Pictured above from left to right: 6.45 ct, 5.28 ct and 2.96 ct all from Plush, Oregon.

Colors:  yellow, orange, red or green; sometimes more than one color is seen in zones within the same stone leading to interesting color patterns.

Clarity:  There is no Type classification for sunstone.  Some sunstones display a golden sheen from reflective inclusions of copper or hematite.

Stone Sizes:  Some large sunstones have been faceted but most of the available gems are less than 10 carats.

Localities:
-Oregon: Several areas in the southeastern part of the state produce this rare variety of gem feldspar unlike any other locality.

-Tanzania, India

Treatment:
-None
Although Oregon sunstone is free from treatment, there was a diffusion treatment done on yellow labradorite/andesine that mimicked some of the rare red and green colors of Oregon sunstone.  Thankfully, this material is no longer being sold regularly.

Gemology:
-Refractive Index:  1.559-1.568 (+/-0.005)

-Birefringence:  0.009

-Optic Character:  Doubly refractive, biaxial positive

-Specific Gravity:  2.70 (+/-0.05)

-Hardness:  6-6.5

Toughness:  poor

-Chemical Composition:  (Na,Ca)Si3O8

-Cause of Color:  Copper

-Absorption Spectra:  Not diagnostic

-Fluorescence:  Usually inert

-Cleavage:  perfect and easy in two directions

-Phenomena:  Aventurescence

Name:  Sunstone is named after the bright glittery inclusions.

Dates:  None

Care:  The ultrasonic and steam cleaner should never be used.  Warm, soapy water is safe.

To see available sunstones, click here.