20 interesting facts about fossilized wood found in the area.
Wood is fossilized when the cell structure is infiltrated with mineral solutions over a long period of time.
It is thought to have been formed when massive amounts of volcanic ash covered trees which then became buried in a lava flow, and associated mud flows.
The silica in the volcanic ash gradually replaced the wood cells and various colours are due to the presence of different minerals such as iron oxide and manganese.
Petrified wood dates back to the Jurassic Age when dinosaurs populated the Earth 140-180 million years ago.
Chinchilla petrified wood is regarded as being the best in Australia as to the colour and quality.
Lapidary enthusiasts from all over the world as well as Australia visit Chinchilla to procure specimens.
Types of trees petrified in Australia belong to the Araucaria family of conifers, tree ferns and cycads – all cone bearing or spore bearing trees.
Petrified wood is very hard and therefore very time consuming to process, being rated between quartz and topaz in hardness. It cannot be scratched with a knife blade.
Diamond saws and drills are needed for cutting and drilling.
Most flat surfaces are polished by machines called Lap Vibrators. These machines use a series of rough and fine silicon carbide grits and then finally on powder impregnated carpet for a mirror finish. This takes approximately 50 hours for the whole process.
Many lapidary enthusiasts use diamond wheels and buffing plates to make cabochons and other shapes for jewellery.
With the great variety of colours and designs in the wood, it is also used for such purpose as inlaying furniture, tiles, coasters, paper weights, bookends, clock faces, bench tops and, being resistant to heat can also be used for pot stands.
Small pieces can be tumbled successfully and are used in a great variety of jewellery.
Examples of the Chinchilla petrified wood can be found in Museums all over the world. It can also be found illustrated in many books and lapidary magazines.
These are designated areas for fossicking close to Chinchilla. Fossickers require a Queensland Fossickers Licence and have to pay a small fee to enter these designated areas (as they are on private property). Picks and shovels are necessary to dig for the unique pieces.
A rare type of petrified wood is found in the Chinchilla area called Pentoxylon. When cut across the grain it exposes a certain design. This design consists of a heart which looks like petals of a flower surrounded by small veins. Each petal of the flower and each separate vein has its own growth rings when viewed through a microscope. Some people have the view that Pentoxylon is a type of cycad, but to this day that is only speculation.
The Pentoxylon tree is thought to have been extinct for 100 million years. Traces of it are only found in Australia, South America and India, suggesting that it grew when these countries where joined together in prehistoric times. It is very scarce and highly prized among collectors.
Tree fern is another type of petrified wood found in this area. When cut across the grain the centre resembles a star which is surrounded by small eyes. It is also very scarce and highly prized by collectors.
The Chinchilla Historical Museum has one of the best collections of Petrified Wood in Australia and can be viewed at most times. (Called the Fred Newman Collection).
The Chinchilla Visitor Information Centre has specimens of Petrified Wood for sale at reasonable prices and can be purchased any day from 9am to 4pm.