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Australia is famous for its exposed rock formations, which are some of the oldest in the world. While these geological attractions are aesthetically pleasing, the real treasure lies beneath the brush and dirt. The underground ironstone boulders contain thin ribbons of Boulder Opal, which has carved a significant niche into the world of jewelry.

Boulder Opal is one of three Australian opals, the other two being Black Opal from New South Wales and White (Crystal) Opal from South Australia. Boulder Opal forms when silica from the sandstone mixes with water in the cracks and voids of ironstone boulders over millions of years. As the rarest of Australian opals, Boulder Opal makes up two percent of all Outback opals, and is mined only in Queensland, Australia—in fact, it has been referred to as the “Queen of Gems.”

Because the veins of Opal are so thin, opal cutters need to leave a layer of ironstone on the back to create a fully-formed stone. Boulder Opal is cut in free form to maximize the shape of the stone, but the presence of ironstone on the surface reduces the value of the Opal. Boulder Opal is unique in its rainbow of color—in fact, the range of color and cut guarantee that no two stones will be the same.

Boulder Opal was first discovered in 1869 within the ironstone mines, and contributed strongly to Australia’s thriving opal production. Australia maintains over 95 percent of the world’s finest opal supply, making it a popular destination for members of the jewelry business.

Jeweler Jennifer Reeves incorporates the brilliant stone into many of her jewelry pieces, creating stunning designs that emphasize the natural beauty of the Boulder Opal. Reeves invites you to visit her “Australian Opals” webpage to witness her extensive Boulder Opal collection.