Minerals and Gemstones of Victoria

Museums Victoria

"...as yet no one country on the broad earth has yielded such as assemblage of varieties of rare and precious gems as Victoria."
Rev. John Bleasdale, 1868
Many early gemstone discoveries in Victoria were made by diggers sifting alluvial deposits for gold.
The wide range of gemstones found in the State reflect Victoria's geological diversity.
Victoria is one of the World's richest gold provinces. It has produced over 2.45 million kg of gold.
Gold was originally found in shallow alluvial deposits. These were exhausted by the 1860s when miners began to work the source - the gold-bearing quartz reefs.
Quartz isn't just a home for gold. It is also the most common gemstone in Victoria. 
Rock Crystal, Amethyst, Smoky Quartz and Citrine varieties all occur in Victoria. Many of these were first found in the 1850s and 1860s during the opening of the major alluvial goldfields.

Amethyst.

Smooth polished amethyst.

Faceted citrine.

Cut and uncut smoky quartz specimens.

When cut in 1971 the Crystal King was the world's largest hand-cut gemstone. It weighs 8510 carats (1.7 kg), meaures 19 x 11 x 6 cm and has 196 facets. 1400 carats were removed during cutting.

Other attractive forms of quartz are also common in Victoria. 
Agates occur in silica-rich volcanic rocks across the state and are often made into cabochons - gems that are shaped by polishing rather than by cutting.

Agates usually form as geodes, or "thunder eggs" when gas bubbles in cooling volcanic rocks are filled in with silica-rich fluids as the surrounding rock cools.

Different coloured bands in the agates come from variations in the chemical composition of the fluids the rock crystallises from.

Opal - another variety of silica - also occurs in Victoria.
Diamonds were first reported in Victoria in the early 1860s in streams and older buried stream channels.
Most diamonds were discovered during treatment of wash-dirt for gold and tin between the 1860s and 1900s. No commercial deposits have been found.
Sapphires - the transparent, coloured gem varieties of corundum - are quite common in some places.
They occur as waterworn crystal fragments in streams and older gravel deposits.

Blue is the predominant colour of the crystals found, but other colours also occur.

Such as green,

purple,

and also yellow and brown.

The pink variety, rubies, are much rarer and smaller than the sapphires.

Not all corundum is found as individual crystals. Some is found embedded in other rocks.

Topaz and other members of the tourmaline family are found across Victoria.
The gem-quality minerals usually form in granite but are rarely found with granite as they wash out and accumulate in alluvial deposits.
Minerals from the garnet group are widespread.
Almandine, spessartine, pyrope, grossular and andradite all occur in Victoria but few crystals are large enough or transparent enough to facet.
Turquoise was discovered in Victoria in the late 1880s.
It was once mined commercially in Victoria.
Iron-rich carbonates have been known in Victoria since the 1860s.
Fine concentric banding formed in cavities around 5 cm across resemble agates and are often called eye-agate.
Other minerals found in Victoria can also be faceted.
Such as zircons.

Or olivine (peridot).

Or anorthoclase (moonstone).

Many minerals from Victoria aren't gems but are just as beautiful in their natural form.
A wide variety of colours and shapes are exhibited by minerals. Some have more than one shape.

Levyne.

Natrolite with analcime.

Natrolite with analcite.

Vivianite.

Vivianite.

Orthoclase.

Chabazite.

Chabazite on calcite

Barite.

Ulrichite.

Sampleite.

Wavellite.

Rhodochrosite.

Fluorapatite

Mrazekite.

Vesuvianite.

Gmelinite.

Thomsonite.

Credits: Story

Many more minerals and gemstones from Victoria, Australia and the rest of the World are on display in the Dynamic Earth Gallery at Melbourne Museum.

More information about the history and geology of gemstones in Victoria can be found in the book "Gemstones of Victoria" by William D. Birch and Dermot A. Henry, published by Museum Victoria.

The book is available through the Museum Victoria shop here: https://museumvictoria.com.au/about/books-and-journals/books/science/new-releases/gemstones-in-victoria/

Credits: All media
The story featured may in some cases have been created by an independent third party and may not always represent the views of the institutions, listed below, who have supplied the content.
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