Opal and Tourmaline
The name of this, the traditional October birthstone, is believed to have originated in India (the source of the first opals brought to the Western world), where in Sanskrit it was called upala, a “precious stone." .” In ancient Rome, this became opalus. Most opals are valued for their shifting colors in rainbow hues – a phenomenon known as “play-of-color.”
The October birthstone’s dramatic play-of-color has inspired writers to compare it to fireworks, galaxies and volcanoes. Bedouins once believed opal held lightning and fell from the sky during thunderstorms. Ancient Greeks thought opals bestowed the gift of prophesy and protection from disease. Europeans long maintained opal to be a symbol of purity, hope and truth. Hundreds of years ago, opal was believed to embody the virtues and powers of all colored stones.
Opals are often referred to by their background “body color” of black or white.
Opal’s classic country of origin is Australia. Seasonal rains soaked the parched Outback, carrying silica deposits underground into cracks between layers of rock. When the water evaporated, these deposits formed opal. Sometimes, silica seeped into spaces around wood, seashells and skeletons, resulting in opalized fossils.
Since opal was discovered in Australia around 1850, the country has produced 95 percent of the world’s supply.
Opal is also mined in Mexico, Brazil, Honduras, Ethiopia, the Czech Republic, and parts of the U.S., including Nevada and Idaho.
The water content of opal gems can range from three to 21 percent—usually between six and 10 in gem-quality material. This, combined with hardness of only 5.5 to 6 on the Mohs scale, makes opal a delicate gemstone that can crack or “craze” under extreme temperature, dehydration, or direct light.
Tourmaline is the newer October birthstone.
The name comes from the Sinhalese word toramalli, which means “stone with mixed colors,” because it often has multiple colors in one crystal.
Very few gems match tourmaline’s dazzling array of colors. Perhaps this is why ancient mystics believed this October birthstone could inspire artistic expression – it has a color palette for every mood. Among the most popular are the pink and red rubellites, the emerald green “chrome” tourmalines, and the neon green and blue-to-violet “paraíba” tourmalines.
Because of its vast range of colors, tourmaline was often mistaken for other gemstones One of the “rubies” in the Russian crown jewels, the “Caesar’s Ruby” pendant, is actually red (rubellite) tourmaline. A Spanish conquistador found green tourmaline crystals in Brazil in the 1500s and confused the stones with emerald. These and other cases of mistaken identity continued for centuries until scientists recognized tourmaline as a distinct mineral species in the 1800s.
Different colors of tourmaline are thought to have their own healing properties. Black tourmaline is believed to protect the wearer and give a sense of self-confidence. Pink tourmaline embodies love and is associated with compassion and gentleness. Green tourmaline promotes courage, strength and stamina.
Tourmaline is given to celebrate the eighth wedding anniversary.
This October birthstone is most commonly found in Brazil, but it is also mined in Afghanistan, Pakistan, Kenya, Madagascar and Mozambique (among other countries in Africa). California and Maine are historically important producers of fine tourmaline in the United States.
Most of the tourmaline mined in Brazil over the centuries comes from pegmatites in the state of Minas Gerais. These subterranean intrusions of magma are the source of a virtual kaleidoscope of gem minerals. In the late 1980s, however, electric green, blue and violet tourmalines entered the gem market from pegmatites in Brazil’s Paraíba State. Scientists found that the intense colors were caused by trace amounts of copper, which had previously not been recorded as a coloring agent in any other tourmaline. In the early 2000s, Paraíba-type copper-bearing tourmalines were also discovered in Mozambique and Nigeria. Overall, prices for the best Paraíba and Paraíba-type tourmalines easily surpass other tourmalines due to their vivid hues, higher color saturation and greater rarity.