Birthstone Series: October’s Opal

This post is the next in a series of twelve discussing the creation and meaning of the
different birthstones. The concept of birthstones dates to the Breastplate of Aaron described in
the Bible. The breastplate was a ceremonial religious piece of armor set with twelve gemstones
representing the twelve tribes of Israel and corresponding with the twelve months of the year.
The birthstone associated with October is Opal.

Stone Origins and Meaning

The name “opal” comes from the sanskrit word “upala” which roughly means “precious
stone”. The gem is comprised of the hydrated silica mineral. Hydrated silica gets its namebecause 20 percent of$
Mohs hardness scale, which measures relative hardness and resistance to scratches, opal falls
between 5 and 6.5. To provide some perspective, ​ diamond ​ falls at 10 and ​ corundum ​ (sapphires,
etc.) falls at 9. Around 90% of the world’s opal comes from Australia. In ancient times, it was
believed that opal wrapped in bay leaf would obscure the wearer from view. Because of this, it
was dubbed ​ patronus forum, or “patron of thieves”.

How to Wear Opal

Opal jewelry is a relatively modern phenomenon. The gem isn’t more widely worn
because of the relative ease with which it scratches. As mentioned before, opal is pretty soft on
the Mohs scale (5 to 6.5) compared to sapphire, for example, which falls at a 9. Because of this,
opal must be worn with strong metal settings and the wearer should take great care to protect the
gem from harm. That being said, it is perfect for those who are looking to wear something


Inspired by history and fantastic story of the opal? At our Joseph Gann Jewelers Boston,
MA location, we feature a beautiful collection of fine jewelry. Have questions? Feel free to stop
by our store or call us at 617-426-4932
. We’d love to chat and answer any questions you might