Tourmaline and Opal Birthstone - October Birthstones

Though most months either have just one birthstone or are known for having only one, some, including the month of October, have two. October’s birthstones are the tourmaline and the opal. While both stones are colorful and beautiful, they are quite different from each other. Here is a close look at both birthstone options for October, their compositions, histories, and places in modern jewelry.

The Tourmaline

The tourmaline gemstone is found in a wide range of colors including blue, red, green, pink, and yellow, among many other colors, though it should never be confused with precious gemstones such as colored diamonds, tanzanite stones, or emeralds. Ancient legend has it that the tourmaline traveled down the rainbow and it is for this reason that it is found in so many colors. Like many other gemstones, it is believed that the tourmaline strengthens both the body and the spirit, particularly the nervous system, blood, and lymph nodes. Additionally, the tourmaline was viewed as a means of inspiring creativity and was thus used as a talisman by artists and writers.

The name tourmaline is derived from the Sinhalese (language spoken in Sri Lanka) “tura mali,” which means “the stone of mixed colors.” In terms of hardness, tourmaline stones are 7 to 7.5 on the Mohs’ scale. Tourmaline stones can be one of many colors, can be a combination of two colors, and can even possess three colors. These colors include black, bluish-black, dark brown, medium brown, yellow, red, reddish purple, pink, and colorless. Tourmaline stones with two colors, bi-colored tourmalines, can be green at one end and pink at other, or, if they are watermelon tourmalines, they will be pink in the middle with a white ring around it, and green at the edges, just like a watermelon. In addition, there are stones that are dichroic, which means, they appear to change different colors when turned on various angles. Tourmaline stones can vary greatly in price, but the most expensive types are the blue indicolite, the green verdelite, and the pink rubelite. Tourmalines are used for making earring, pendants, bracelets, and rings. The tourmaline is sometimes given as an 8th wedding anniversary gift.

The Opal

The opal is the more modern birthstone for October and is also used as the gemstone for one’s 13th wedding anniversary. The name opal comes from the Latin word “upala,” which means “precious stone.” Opals date back fifty-to-sixty million years ago to the Cretaceous period. Decomposed rocks combined with ground water created silica gel that accumulated and hardened in the Earth’s cavities. These formations are what we know as opals today. The chemical formula for opals is Si02.nH20.

There are two main types of opals; common opals and precious opals. Similar to colored diamonds, opals with higher color intensity are far more valuable. Additionally, like colorless diamonds, the more brilliant the opal, the more valuable it is. There are crystal-like translucent light opals and “milky,” opaque light opals. These types are considered more common though brilliant light opals are very pricey. Some brilliant opals can be even pricier than some black and boulder opals, which are rather valuable. Fine black opals can cost more per carat than colorless diamonds.

Both tourmaline and opal stones are remarkable gemstones. Though they each have unique characteristics, both scientifically and visually, they both make terrific choices for an October birthstone. Nature has given us a wide selection of natural gemstones of different substances and colors. However, each and every gemstone, from diamonds to colored diamonds to tanzanite stones to opals, has its own “personality,” which is suitable for a certain “type,” whether it is their birthstone or not. 

Contributor: Benji Margolese

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