Destructive Gemstone Testing

Destructive gemstone testing, done carefully, can help gemologists with difficult gem identifications. Learn the right techniques with our 5-part series.

0
HomeLearning CenterGemologyGemstone Testing and IdentificationDestructive Gemstone Testing
By Donald Clark, CSM IMG

Why do geologists have an easier time identifying gems than gemologists? Because they can more readily conduct destructive gemstone testing. Geologists can scratch gems to test their hardness, check their reaction to acids, and even put them in a torch's flame to identify them.

Turquoise stones are sometimes coated with thin layers of wax to improve their appearance. A hot point test on a tiny, inconspicuous spot can make any wax present bead like perspiration on the stone without actually touching the surface of the stone or damaging it. Destructive gemstone testing, like a hot point test, is a
Turquoise stones are sometimes coated with thin layers of wax to improve their appearance. A hot point test on a tiny, inconspicuous spot can make any wax present bead like perspiration on the stone without actually touching its surface or damaging it. Destructive gemstone testing, like a hot point test, is a "last resort" for gemologists trying to make a difficult gem or treatment identification. When done carefully by a professional, these tests shouldn't lessen the value of a gem or jewelry piece. "Turquoise Cuff with Vintage Beads" by Melissa Ingram is licensed under CC By 2.0.

These destructive tests are informative but, obviously, they damage the gems and reduce their value. Gemologists normally use complex optical and microscopic examinations to identify unknown gemstones without damaging them. Unfortunately, standard gemological tests occasionally fall short of positive identification. In these cases, gemologists must resort to destructive gemstone testing. With great care, however, these tests can be conducted in a limited manner without diminishing the value of the stone.

Our five-part series on destructive gemstone testing offers concise explanations of the principal procedures.

Destructive Tests: Scratch Testing

Destructive Tests: Streak Tests

Destructive Tests: Hot Point

Destructive Tests: Acid Testing

Destructive Tests: Dye Tests

Donald Clark, CSM IMG

Donald Clark, CSM founded the International Gem Society in 1998. Donald started in the gem and jewelry industry in 1976. He received his formal gemology training from the Gemological Institute of America (GIA) and the American Society of Gemcutters (ASG). The letters “CSM” after his name stood for Certified Supreme Master Gemcutter, a designation of Wykoff’s ASG which has often been referred to as the doctorate of gem cutting. The American Society of Gemcutters only had 54 people reach this level. Along with dozens of articles for leading trade magazines, Donald authored the book Modern Faceting, the Easy Way.
View All Articles

Related Articles

More Articles
Identifying Opal Patterns

Identifying Opal Patterns

Opal connoisseurs all have their favorite opal patterns. Learn how to identify the patterns of these beautiful gems with plenty...
Read More
Eight Opal Types Explained

Eight Opal Types Explained

Opal is a complicated gemstone, and many factors affect its price. Learn how to distinguish these eight opal types and...
Read More
Ultraviolet Testing and Gemstone Identification

Ultraviolet Testing and Gemstone Identification

Ultraviolet testing can be crucial for gemstone identification. Learn the basics of this technique as well as how to make...
Read More
An Introduction to Gem Identification

An Introduction to Gem Identification

Gem identification is part detective work, part art. Learn how gemologists can distinguish gem species and determine whether a stone...
Read More

Latest Community Discussions

A concise but informative article title goes right here.

A concise but informative article title goes right here.

Read More
A concise but informative article title goes right here.

A concise but informative article title goes right here.

Read More
A concise but informative article title goes right here.

A concise but informative article title goes right here.

Read More
A concise but informative article title goes right here.

A concise but informative article title goes right here.

Read More

Never Stop Learning

When you join the IGS community, you get trusted diamond & gemstone information when you need it.

Become a Member

Get Gemology Insights

Get started with the International Gem Society’s free guide to gemstone identification. Join our weekly newsletter & get a free copy of the Gem ID Checklist!