Hardness : 2.5
Specific Gravity : 1.3
Doubly Refracting (bi-refraction) : none
Abalone is considered an Organic gem material, in that respect, it is similar to Coral. The iridescent color play found in Abalone is naturally occurring. The Abalone is a mollusk that can be found in the United States along coastal California. The Abalone is unmistakable. The shell is rounded to oval, and has a body whorl with a series of holes along the edge.
The Aragonite (calcium carbonate) tiles which make up the structure of the Abalone shell, are stacked like bricks, which give the Abalone shell its great strength. When the shell is struck, the tiles do not shatter. Instead they slide and the protein between the layers stretch to absorb the energy of the blow. The dust created through the grinding and cutting of abalone shell is toxic and carvers and cutters must be careful so as to not inhale the fine dust particles. A fine particle dust mask, a ventilation system and wet grinding are required to work the shell safely.
Abalone may also be called Mother of Pearl, or by the name Sea Opal, due to the iridescent blues and greens that are produced when polished, which is similar to the color play of an Opal.
It is often used in jewelry, commonly seen as pendants or earrings. During the late 18th and well into the 19th centuries, mussel shells from the Mississippi River were being used for the mass production of buttons. The result was a lot of pearly white buttons, and many mussel shells with 3 or more holes in them which can still be found along the Mississippi River. Mother of Pearl is often found in jewelry and inlay work such as that found on guitars and also in such things as pistol grips.
In New Zealand the native New Zealanders call their Abalone by the Maori name, Paua. The Maori people of New Zealand have been carving these shells into beautiful creations for many centuries.