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Sunstone

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

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Copper

Tiny copper platelets can cause the prized red hue in Oregon sunstone.

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Color zones

Some sunstones exhibit attractive color zoning.

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Matte finish

Matte-finish facets can provide an interesting and attractive contrast.

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Glitter

Sunstone’s glittery sparkle shows up even in its rough form.

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Bicolored

Some sunstone rough displays interesting zoned colors.

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Desert Sun

The Ponderosa mine produces many lovely specimens like this one.

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Tools

Overview

About Sunstone

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.

Sunstone Description

Sunstone History and Lore


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

Treatments

There are a number of processes used to alter the color, apparent clarity, or improve the durability of gems.

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Synthetics

Some gemstones have synthetic counterparts that have essentially the same chemical, physical, and optical properties, but are grown by man in a laboratory.

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Imitations

Any gem can be imitated—sometimes by manmade materials or by natural materials chosen by man to impersonate a particular gem.

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gem love

Why We Love This Gemstone

1
Glittery

Reflective inclusions in sunstone’s phenomenal varieties cause a distinct and lively glitter called aventurescence.

2
Natural

Oregon sunstone’s colors don’t result from treatment. The gem’s all natural and it’s mined in the United States.

3
“Spinel red”

Red-colored Oregon sunstone is often marketed to consumers as “spinel red.” Its vivid hue rivals spinel and even ruby.

Quality Factors

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

Color

quality factors

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

Clarity

quality factors

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

Cut

quality factors

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

Carat Weight

quality factors

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

Sunstone Quality Factors: The Comprehensive Guide

Research

Explore sources, gemological research, and the role of gems in history.

Mixed-cut Oregon sunstone

Oregon Sunstone Update

Duncan Pay , Apr 30, 2015 Read Article

A Sunstone Odyssey,
Part 1: The Ponderosa

Duncan Pay, Robert Weldon, and Kevin Schumacher , Oct 23, 2013 Read Article
Large sunstone rough from the Ponderosa mine in Oregon

Ponderosa Sunstone Update

Duncan Pay , May 11, 2018 Read Article

What it Takes to Mine Oregon’s Sunstone

, Oct 25, 2013 Read Article