Hidden Treasure – Glenalva

Dramatic changes in climate and environment millions of years ago resulted in gems of amazing beauty in all colours of the rainbow

Between 70 and 40 million years ago, the Earth’s crust shifted, moving Australia closer to its current position and hot spots of molten rock developed below. Pressure built and eventually volcanic mountains erupted, spewing out lava and ash. Sapphires and zircons that had formed deep in the Earth’s crust were blasted out as crystals in this volcanic ash. 

→

From about two million years ago, weathering and erosion began to release the sapphires from the volcanic materials that encased them. These hidden treasures now lie waiting to be discovered!

→

Glenalva fossicking area
The Glenalva fossicking fields have produced a wide variety of good quality stones, predominantly greens or blue-greens and yellows, with occasional black star sapphires, parti-colours, blues and pinks. The rare blues, and a fair proportion of the greens, are of high quality. Glenalva is just one of the Fossicking Areas in the Sapphire Gemfields that were set aside in 1985 for recreational and tourist fossicking. Only hand tools can be used for fossicking in this area.

→

Glenalva facilities and camping 

Camping is allowed for a maximum period of three months. Camping permits and fossicking licences can be obtained online at qld.gov.au or from authorised agents. There is no water at Glenalva, so you will need to have your own supply. There are no facilities, however, there are many suitable camping spots along the lightly timbered ridges. The main area is near the western boundary.

→

Fossicking licences 

Within the Sapphire Gemfields region, 11 areas are designated for public fossicking and cover thousands of hectares of sapphire-bearing ground. 

Fossicking licences are a legal requirement. They are inexpensive, come with a set of maps and rules, and can be purchased online at qld.gov.au or at various local businesses. 

Hand tools and mining gear are also available for sale or hire.

→

Finding sapphires

Sapphires can be found in all layers of sapphire-bearing ground, however most stones will be concentrated in what is known as the wash. The wash is the section of dirt found on, or just above, the floor or bedrock of an ancient underground creek bed. A long time ago, sapphires were transported, via water flow, from the volcano where they were formed. As sapphires are heavier than most materials, they naturally drop to the bottom into the layer of wash, where they settle alongside the larger stones often called ‘billy boulders’.

Fossicking licences are a legal requirement. They are inexpensive, come with a set of maps and rules, and can be purchased online at qld.gov.au or at various local businesses. 

Hand tools and mining gear are also available for sale or hire.

→

Shallow wash rarely exceeds a depth of 500 mm. Workings typically expose about 300 mm of grey, soily wash containing billy boulders, pebbles and cobbles of chert and silicified sandstone. 

This overlies a thin layer of light-grey clayey material, described locally as decomposed volcanic ash. The wash rests on a clay bottom, which overlies basement rocks or bedrock.

↓

Did you know? 

  • Sapphires come in all shades of the rainbow, although they are typically a deep, royal blue. 
  • Sapphires and rubies are made of corundum (aluminium oxide) – the second hardest gemstone after diamonds. The various colours in these corundum stones are caused by additional elements. 
  • The stunning yellow and green-hued sapphires result from a combined addition of ferric and ferrous iron.

Location

Open in Apple Maps
Open in Google Maps
Open in What 3 Words

what3words

Download the what3words app to help you follow the Trail.
Here are the ///what3words identifiers for this location and for the three closest stops:

You are here: ///unveiling.immediate.control

Where to next?

Pacey’s Yellow – Glenalva – ///unveiling.immediate.control

Welcome to Willows – ///spaced.printed.particularly

Sapphire Reflections – Anakie – ///inner.invoked.haste

Scroll to Top