Historical information

Actinolite is usually found in metamorphic rocks, such as contact aureoles surrounding cooled intrusive igneous rocks. It also occurs as a product of the metamorphism of magnesium-rich limestones.

Pyrite is usually found with other sulfides or oxides in quartz veins, sedimentary rock, and metamorphic rock, as well coal beds, and as a replacement mineral in fossils.

Significance

Actinolite is an amphibole silicate mineral. It is named after the Greek word "aktinos" meaning “ray” in allusion to the mineral's fibrous nature. Fibrous actinolite is a type of asbestos and was once mined along Jones Creek at Gundagai, New South Wales.

Pyrite or "Fool's Gold" is the most common sulfide mineral. It is named after the Greek "pyr" meaning "fire" because it can be used to create sparks needed for a fire if struck against metal or a hard surface. Due to its gold colour, pyrite can be mistaken for gold and often forms alongside it, causing small amounts of gold to be present in rocks containing pyrite. Most importantly, pyrite is an ore of gold. Pyrite is sometimes used as a gemstone but is not great for jewellery as it easily tarnishes. In some fossils of ammonites – shelled cephalopods that died ~66 million years ago – pyrite also replaces the shell.

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.

Physical description

A small-medium-sized solid specimen with the minerals actinolite (dark green fibrous) and pyrite (brassy) with shades of brown, black/grey, and white. Actinolite is an amphibole mineral in the tremolite-actinolite series of calcium, magnesium, and iron silicates. Pyrite is an iron disulfide mineral.