It is made up of andalusite. Andalusite is a rock-forming mineral, sometimes found in granite or schist. It is often used to make glass, ceramic products, chemicals, and heat-resistant bricks as it can withstand high temperatures without changing. The chiastolite contains particles of graphite, which arranges in geometric patterns. When crystal growth occurs in the rock, the granite particles concentrate at crystal interfaces and can result in cross shapes. These ‘cross stones’ have been valued and used for their spiritual or religious meaning and used as charms, gems, or amulets.
Chiastolite was first discovered in 1754, seen in a description in a published book by a palaeontologist, Franciscan priest, and Spanish author, Jose Torrubia. Deposits have been found in Australia, France, the USA, Chile, Canada, Spain, Brazil, Sri Lanka, and Russia. Deposits have been found in Western Australia and South Australia.
This particular specimen was found in Bimbowrie, South Australia. Other chiastolite specimens have been found in Bimbowrie, along with jasper, quartz, and aventurine in the form of rolled pebbles or schist.
This chiastolite specimen is socially and historically significant. It is a very rare sort of andalusite mineral. It is from one of only two locations where it is regularly found in Australia. The carbon cross has made it an important religious symbol in the past. Its ability to withstand high temperatures has made it a common ingredient in heat-resistant bricks and ceramics today.
This specimen is part of a larger collection of geological and mineral specimens collected from around Australia (and some parts of the world) and donated to the Burke Museum between 1868-1880. A large percentage of these specimens were collected in Victoria as part of the Geological Survey of Victoria that begun in 1852 (in response to the Gold Rush) to study and map the geology of Victoria. Collecting geological specimens was an important part of mapping and understanding the scientific makeup of the earth. Many of these specimens were sent to research and collecting organisations across Australia, including the Burke Museum, to educate and encourage further study.
A metamorphic mineral consisting of andalusite, with a cross shaped graphite pattern in colours of grey, brown and yellow