◂ BACK TO GEM ENCYCLOPEDIA

SUNSTONE

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

SUNSTONE
See Gem As

Overview

ABOUT SUNSTONE

Diamond forms under high temperature and pressure conditions that exist only about 100 miles beneath the earth’s surface. Diamond’s carbon atoms are bonded in essentially the same way in all directions. Another mineral, graphite, also contains only carbon, but its formation process and crystal structure are very different. Graphite is so soft that you can write with it, while diamond is so hard that you can only scratch it with another diamond.

Sunstone Description

Sunstone History and Lore

 

FELDSPAR

Sunstone is a member of the feldspar group of minerals.


ADVENTURESCENE

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.

SYNTHETICS

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

IMITATIONS

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

Why We Love This Gemstone

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

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

CLARITY

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

CUT

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

CARAT WEIGHT

CARAT WEIGHT
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.

{Oregon Sunstone Update  Duncan Pay , Apr 30, 2015} - image
Oregon Sunstone Update Duncan Pay , Apr 30, 2015
{A Sunstone Odyssey, Part 1: The Ponderosa  Duncan Pay, Robert Weldon, and Kevin Schumacher , Oct 23, 2013} - image
A Sunstone Odyssey, Part 1: The Ponderosa Duncan Pay, Robert Weldon, and Kevin Schumacher , Oct 23, 2013
{Ponderosa Sunstone Update  Duncan Pay , May 11, 2018} - image
Ponderosa Sunstone Update Duncan Pay , May 11, 2018
{What it Takes to Mine Oregon’s Sunstone  , Oct 25, 2013} - image
What it Takes to Mine Oregon’s Sunstone , Oct 25, 2013

RECOMMENDED READING

You Might Also Like

YMAL AJP
AJP®: New 5-Day Program Offered Worldwide
Learn About NextGem
GIA NextGem™ Diamond Training for Retail
Explore GIA Laboratory Promotional Offers
Explore GIA Laboratory Promotional Offers
Shop the GIA Store
Shop the GIA Store