Boulder Opal. Jewelry can be made on request, do not hesitate to contact me, leave a message with what you would like to have. Cut: cabochon Dimensions: 31 x 11.4 x 6.3 mm Weight: 16.68 carats Treatment: None - natural stone. Origin: Winton, Queensland, Australia Reference: FD44 You will always receive the exact stone pictured with the same colors. Additional videos or photos can be taken with a different type of lighting. Please check the dimensions carefully before purchasing. Returns are accepted within 14 days provided the items remain in their original condition. No justification necessary if you wish to return an opal. Shipping costs cannot be refunded. If you have any questions, do not hesitate to contact me, I will be happy to answer them. --------------------------------------------------------- Boulder Opal, also called Pebble Opal, is native to the Queensland region of Australia. They are found more precisely in the regions of south-west Queensland: Quilpie, Yowah, Eromanga. The sedimentary rocks of this region date from the Cretaceous period (-140 million to -65 million years BC). Most Opals come from these very arid regions where, during periods of heavy rainfall, tiny particles of silica have been dissolved in the water. When the water evaporated, these pieces of silica crystallized into small spheres in the parent rock and gave birth to Opals. The first Boulder Opals were discovered in 1869 and the first mine was opened in 1871 in Quilpie County. Very quickly a few miners arrived in this region to exploit this wealth, such as Bekerlman and Lambert who presented Opals at the “London Gem Exhibition” of 1893 which immediately caused a sensation. Characteristics of Boulder Opal. Boulder Opal comes in the form of Opal veins trapped in iron ore. It is generally cut in such a way as to leave part of this ore around the Opal veins. Its size is therefore quite delicate due to the hardness of iron ore compared to that of Opal. But thanks to this particularity, these Opals are renowned for being more solid than their counterparts. Boulder Opal is particularly interesting because the contrast of the black rock matrix brings out the multiple luminous play of colors of the Opal. For Boulder Opals, the color schemes are most often in blue-green tones. We generally find them cut in the direction of the Opal vein with the iron ore supporting the back, the surface of the stone is then covered with Opal; or in transverse size perpendicular to the Opal veins to highlight the stripes of silica trapped in the parent rock.