Geological specimen - Agate and Quartz pebbles

Historical information

Agate occurs when amygdales (gas pockets) form in the upper levels of basaltic lava flows. If these pockets or bubbles are iniltrated by water bearing silica in solution, the fluid dries and hardens in layers, forming round or egg shaped nodules or geodes within the rocky matrix. Agate is formed of a silica mineral chalcedony similar to quartz. Although relatively common and semi-precious, agate has been prized since at least 1450 BC - an intricately carved agate seal was found in the 2015 excavation of a grave belonging to a Mycenaeum priest or warrior near Pylos in Greece. Agate is also used in jewellery and other decorative or ritual purposes due to its often striking appearance.

Quartz is found all over Australia, including Beechworth in Victoria. It is formed in deep-seated igneous rocks and crystallized through hot aqueous solutions. It can have two forms; Microcrystalline quartz or Crystalline quartz. Microcrystalline quartz is a fine grain quartz where crystalline quartz is often a large crystal. The colour of quartz can vary.

These specimens were collected in Victoria in the vicinity of the Burke Museum. Victoria and other regions of Australia were surveyed for sites of potential mineral wealth throughout the 19th Century. The identification of sites containing valuable commodities such as gold, iron ore and gemstones in a locality had the potential to shape the development and history of communities and industries in the area. The discovery of gold in Victoria, for instance, had a significant influence on the development of the area now known as 'the goldfields', including Beechworth; the city of Melbourne and Victoria as a whole.

Significance

The specimens are significant as examples of surveying activity undertaken to assess and direct the development of the mineral resource industries in Victoria and Australia, as well as the movement to expand human knowledge of earth sciences such as mineralogy and geology in the nineteenth century.

Physical description

Geological specimens of Agate and Quartz respectively; the fist-sized piece of Agate has peach/coral colouring with grey concentric patterning and the smaller piece of quartz is a uniform yellow/orange shade.

Inscriptions & markings

Existing label:
Local pebbles / (agate and / quartz /
(yellowish) / egg-shaped). / BB

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