Boulder Opal Facts, Information and Description

The gemstone Opal is the official October birthstone as adopted by the American National Association of Jewelers in 1912. It is also the birth stone for the Zodiac sign of Libra. See the birthstone tables for additional references to this stone.

Boulder opal is found in Australia where precious opal forms in veins and patches within brown ironstone boulders. When the opal is mixed through the ironstone it is called matrix opal. Hardness ranges between 5.5 and 6 on the Mohs scale.

Boulder opal is very durable due to the ironstone backing the opal forms on.   Because water content within the opal is very low it almost never cracks or crazes as it ages.

See facts, legends, colors and varieties of opal for a more extensive discussion on opals.

Healing Properties:

Aids inner beauty, faithfulness, and eyesight and helps recall past lives.

Boulder Opal Jewelry and Cabochons

Designer jewelry made with boulder opals.  A selection of freeform opal cabochons and rough available for custom jewelry design.

An index to Opal jewelry by type.

A variety of boulder, Yowah and Koroit opals in shades of green, pink, coral, aqua, blue and green.

All other stones in the large
image are boulder opals.

see other October birthstones

Opal is also listed as a birth/natal or star stone in the following birthstone tables:

Modern - October
Mystical - April
Ayurvedic - October
Sun Sign (Star Sign) - Aquarius
Sun Sign (Star Sign) - Libra
Hindu - March