Organic Gem Materials
Not everything used as a gemstone is a mineral—or even a rock.
Some gem materials were produced by living organisms or originated through biological processes. These are commonly grouped together as organic gem materials.
Pearl, amber, coral, shell, and jet are familiar examples. They come from very different sources, but each has an important connection to once-living or living organisms.
Organic Gem Materials — Learning Series 003 (PDF)
What Makes a Gem Material “Organic”?
Most familiar gemstones are minerals. Quartz, turquoise, garnet, fluorite, and many others formed through geological processes and have characteristic chemical compositions and structures.
Organic gem materials are different.
They originate from plants or animals or are substances produced by them. Some are used almost as they occur in nature, while others may be cut, polished, carved, drilled, or fashioned into jewelry and decorative objects.
Among the best-known examples are:
- Amber — fossilized tree resin
- Pearl — produced within certain mollusks
- Coral — skeletal material produced by colonies of marine animals
- Shell — including mother-of-pearl and other attractive mollusk shell
- Jet — an organic material formed from ancient wood under particular geological conditions
Other biologically derived materials have also been used for ornamentation throughout human history.
Amber, Copal and Ancient Resin
Amber is especially fascinating because it began as resin produced by ancient trees. Over millions of years, chemical and geological processes transformed some of that resin into the material we call amber.
You may also encounter copal, a younger resinous material that has not undergone the same degree of transformation as amber.
Both can occasionally preserve insects, plant fragments, and other evidence of the environments in which the resin originally formed.
Organic Does Not Mean Soft or Fragile in the Same Way
Organic gem materials vary considerably in their properties, but many require more care than common mineral gemstones.
Heat, chemicals, prolonged sunlight, dryness, moisture, and abrasive cleaning can affect different organic materials in different ways. Pearl, coral, amber, shell, and jet should not automatically be treated the same way you would treat quartz or agate.
Knowing what a material actually is matters when cutting it, cleaning it, wearing it, or storing it.
What About Fossils and Fossilized Material?
This is where the terminology can become confusing.
A fossil may preserve evidence of something that was once alive, but that does not necessarily make the finished material an organic gem material in the gemological sense.
Petrified wood, agatized coral, dinosaur bone, stromatolites, and other fossil materials may have had biological origins, but much or all of the original material can be replaced or altered by minerals during fossilization.
They are fascinating lapidary materials in their own right—and a subject worth exploring separately.
A Guide to Organic Gem Materials
Learn more about these unusual materials in Learning Series 003 — Organic Gem Materials.
The guide introduces several important organic gem materials, where they come from, how they differ from mineral gemstones, and some of the characteristics that make them interesting to collectors, lapidaries, and jewelry lovers.
Organic Gem Materials — Learning Series 003 (PDF)
More Organic Gem Material Topics Are Coming
Future Learning Center pages can take a closer look at individual materials such as amber, copal, pearl, coral, shell, and jet, along with related subjects such as fossil materials and ancient life preserved in stone.
Some gemstones begin deep within the Earth. Others begin with something that was alive.