Spencer, Navajo - Sterling Silver
NBT705 - 6 1/2"
100% solid silver won't tarnish but it is too soft to use for making jewelry - it could easily be scratched, dented and bent. Sterling silver has a small amount of one or more other metals usually copper, added to the silver. To be called sterling silver, the alloy must contain at least 92.5% pure silver. Sterling silver alloy is harder than pure silver but the added metals also can cause discoloration or tarnish. Read more about silver.
What is Spiny Oyster?
Spiny oyster, not surprisingly, is an oyster that is covered with spines. Like coral or mother-of-pearl, the shell of spiny oyster is considered an organic gemstone. The portion of the shell used to make jewelry is aragonite, which consists of calcium carbonate (CaCO3). Aragonite has the same chemical formula as calcite. Spiny oysters are found along the Atlantic coast of Baja California and Baja Mexico. Common colors vary from orange, found in shallow waters, to red and purple from deeper waters. The shell is also found in white, yellow, pink and brown. Polished shell has definite striations and color variation. Red spiny oyster has been used as a subsititute for coral.