Information on the Traditional October Birthstone

The traditional October birthstone is opal. In the early 1950's, the Jewelry Industry Council suggested the pink tourmaline as an alternate for the October birthstone. Although the alternate pink tourmaline was approved by the American Gem Society and the National Retail Jewelers Council, many still chose the traditional opal.

Opal is a sedimentary rock formed of silica. It is hardness rated at a 5.5 to 6.5. It has a relatively high water content of 3 percent to 21 percent. Since opal is a brittle stone, if it dries out it can crack. Extreme temperature changes can also cause the opal to crack. Since the opal is a fairly soft stone, it should not be worn during physical activity as it may scratch. If the climate is particularly dry, the opal can be stored in an airtight bag with a damp cloth to help it retain its moisture content.

There are several types of opals. The types include: white opals, black opals, fire opals and crystal opals. Black opals are not black as the name suggests, but instead they have a dark body with a wide array of bright colors in the stone. These opals are the most sought after and are typically mined in New Zealand. White opals have a white body with a few bright colors shining through. These are usually mined in South Australia. A crystal opal has a clear body tone and you can usually see through the stone. Crystal opals boast the same brightness as a black opal. The fire opal usually mined in Mexico and has an overall orange or reddish hue.