October Birthstone – Opal (or Tourmaline)

What’s the Birthstone for October?

The name “opal” originates from the Greek word opallios, which meant “to see a change in colour.”

Opal’s characteristic “play-of-color” was explained in the 1960s, when scientists discovered that it’s composed of microscopic silica spheres that diffract light to display various colors of the rainbow. These flashy gemstones are called “precious opals.” Those without play-of-color are “common opals.”

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. 

Wearing opal jewellery is well worth the extra care, though. 


Tourmaline is the birthstone for October according to both the modern list, which is most actively used. Opal is the gemstone on the ancient list for October, but Tourmaline is the one most frequently used.

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.

The tourmaline birthstone is rated 7 to 7.5 on the Mohs scale of hardness and is generally suitable for everyday wear.

Both of these birthstones come in a spectacular array of colors sure to please you or your loved one born in October.

Shop loose Opal and Tourmaline in-store today.