Silcrete and chert can create sharp flakes and have been important materials for stone tool making in Australia. Silcrete was commonly used and widespread. Heat treatment of silcrete made the rock easier to fashion into flakes.Partly worked, incomplete Aboriginal rock blanks. The collection includes rocks of silcrete, quartz, and chert. 8969.26 is quartz chert. 8969.37 is a flint stone with a vein of quartz. The dark brown rock is silcrete with more iron than others (possibly 8969.41). 8969.45 is Quartz. aboriginal, tool, blank, rock, scraper, aborigines, quartz, silcrete, chert, stone tools, quartzite, flaking, flake tools, archaeology

Chert is a sedimentary rock composed of microcrystalline or cryptocrystalline quartz. While usually biological in origin, chert may also occur as a chemical precipitate or a diagenetic replacement--the product of petrified trees. Chert, also known as flint, was a common tool for early peoples during the stone age. It forms in limestone and chalk sediments as silicon dioxide microcrystals which grow into nodules of chert. Chert is found in many mines across the Northern Territory, however this specimen is sourced from the Mount Todd gold mine in Katherine. Its use in weaponry, both during the Stone Age and during the 18th century. Chert produces a spark when struck against steel, meaning t hat it can be used to start fires and fire guns. Chert was thus used in flintlock firearms, in which the gunpowder is ignited by a flint hammer striking a steel plate. Chert was commonly used in the Stone Age as a result of conchoidal fracturing causing very sharp edges, allowing early peoples to fashion weapons and cutting tools. It also rates a 7 on the Mohs Scale, making it a very hard and durable stone that maintains its sharpness. As a result, the significance of chert as a signifier of early indigenous Australian life makes this specimen important. It is also known that chert is a valuable mineral that was used as a trading commodity. Chert has also been valuable during the 1700s, proving itself to a be an important historical specimen in matters of war. A solid silicon dioxide mineral in shades of brown, white, and beigeburke museum, northern territory, chert, flint, minerals, geological specimen, katherine, mount todd gold mine, katherine northern territory

Galena occurs in a range of deposit contexts, often in metalliferous veins, such as Broken Hill, Australia; Coeur d’Alene, Idaho, United States.; Clausthal Zellerfeld, Germany; and Cornwall, England. Large deposits also replace limestone, dolomite, or occasionally organic matter, or have a contact-metamorphic origin. Galena is additionally found in cavities, brecciated (fractured) zones in limestone and chert, and in coal beds. This specimen was recovered from Broken Hill NSW and is 60% lead with 8-12 oz/silver to the ton.Galena or 'lead glance' is a grey lead sulfide and the chief ore mineral of lead. It forms isometric crystals in which the ionic lattice is similar to sodium chloride. Galena is brittle and easily weathers to secondary lead minerals, with the upper part of mineral deposits often containing cerussite, anglesite, and pyromorphite. It usually contains silver, which is mined along with its lead content. Other commercially important minerals that form in close association with galena are antimony, copper, and zinc. 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 small-sized solid specimen containing one mineral with a sparkly silver metallic lustre exterior and pastel-grey interior.geological specimen, geology, geology collection, burke museum, beechworth, galena, lead sulphide, alfred selwyn, broken hill