BOULDER OPAL SPLIT
A Boulder Opal Split for collection or jewellery making. A large sized Opal specimen in Purple, Blue and a splash of Orange colour. A really lovely pair of Aussie stones. This specimen is from quality Boulder Opal gemstone. You can see two good seams split and a little on the side.
10cm x 11.3cm x 7.4cm, 1168g.
nH2O Hydrated Silicon Dioxide.
Opal has been a popular gem for many centuries and has a very interesting structure. The name opal comes from the Sanskrit name for precious stone upala. Opal structure is not crystalline and considered a mineraloid. The chemistry of Opal is primarily SiO2 and varying amounts of water. The amount of water varies from 5 -10% and greater. This water can help geologists determine the temperature of the host rock at the time the opal formed.