Boulder Opals and their Geographic formation !!!!
Boulder opals are found only in the state of Queensland, Australia. Queensland produces boulder opal, a unique type of opal which is found attached to a host rock, ironstone. Boulder opal is unique to Queensland and occurs in deposits in weathered sedimentary Cretaceous rocks in the west of the state.
Formed in areas of Ironstone, Boulder Opals are created when the host rock (Ironstone) forms with/as part of the opal when the gem is formed in cracks/voids within the host rock. The resulting opal is often a thin vein laid on (natural) the Ironstone.
Geographical location of Boulder Opal
The Queensland opal fields are within a belt of deeply weathered Cretaceous sedimentary rocks known as the Winton Formation, which extends in a northwesterly direction from the New South Wales border at Hungerford stretching west of Cunnamulla, Quilpie, Longreach and Winton to Kynuna, a distance of about 1000 km.
Boulder Opal, with colours ranging from black or light, is sourced from areas in Western Queensland, which are cut to incorporate the brown host Ironstone and are valuable due to their high demand. Around Andamooka in South Australia, where the host-rock is quartz which is lighter in colour, the Boulder Opal is also referred to as a ‘Painted Ladies’.
Boulder Opal is the national gemstone of Australia, as it produces the largest percentage of the world’s supply, 97%. Boulder opal is highly durable, therefore care and storing is made relatively easy; Cleaning however must be done with caution, and is best to take place with warm water and a soft cloth, though soaking the stone is not recommended.
Watch out for the interesting visual video of boulder opals Here
It's believed that perhaps 30 million years ago, lots of silica was released into a solution which filled cracks in the rocks, layers in clay, and even some fossils. Some of them became precious opals. It takes about 5 to 6 million years to make a 1 cm opal to mature.
Check out the Limanty's boulder opal collection and grab it to experience the real boulder opal magic HERE
