International School of Gemology August 6, 2022

ISG: The Story of Abalone Shell

Abalone (pronounced: a · buh · low · nee) is a large marine gastropod mollusk that has been harvested for decades both for its meat and iridescent shell that is made into jewelry. The unique coloring of the mother-of-pearl type secretions that form the shell are unlike any other in the world.

Most abalone are found in the cold waters of the coast off of North America, as well as South Africa, Japan, Australia, and New Zealand where it is called by its Māori name: “paua shell”. At last report, harvesting of abalone in the waters off the northern United States was closed due to depleted population of abalone due to several environmental factors. However, harvesting in other areas appears to be ongoing. 

Below is a New Zealand abalone half shell.

New Zealand Abalone Shell

Abalone shells are sometimes used by simply drilling holes and stringing beads and pendants. Others are carved into intricate shapes as abalone shell is quite durable and lends itself to all levels of jewelry design. The unique colors of abalone shell create a beautiful rainbow effect with the result that no two abalone shells are ever alike, and all bring their own iridescent beauty to the wearer. With the shell being available at very reasonable prices, abalone has become a favorite among jewelers in tourist destinations and pearl designers who want to add the unique and unusual to their design production. 

Gemological Properties

Source: New Zealand, Australia, Japan and United States. Shells from small sea creatures of the abalone family. Most popular is “rainbow abalone” as seen above.

Chemical: Calcium Carbonate

Formation: Shells of the abalone

Crystal System: None. Organic

Unusual Properties: Can produce abalone pearls but these are rare.

Wearability: Excellent for jewelry items.

RI: None

Birefringence: None

Optic Character: None

Absorption Spectra: None

Specific Gravity: Varies

Hardness: Varies

Transparency: Opaque to translucent

Special Identifying Properties and Tests: Abalone shell jewelry is rather unique for the intensity of colors that offers more variety of colors that ordinary mother-of-pearl.

Imitations: None known.

Join us each week for this new educational series on the amazing world of gemstones.

Robert James FGA, GG

President, International School of Gemology

Visit the ISG website to learn more about our world-class programs in gemology and jewelry appraisal at our low tuition rates. International School of Gemology

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