Opal Types

Below is the entire list of Johno's blog posts relating to Opal Types.

Experimenting with opal

22 June 2020 by Johno

Trying something different with your opal Most opal lends itself to cutting some form of cabechon. Some will have rounded tops and others, where the opal has a band of colour, will have flattened tops to ensure we get the most out of our opal. When we have thin layers of opal...

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Some Beautiful Andamooka Matrix Opal

2 December 2019 by Johno

Andamooka Matrix Opal Andamooka Matrix opal is a unique form of opal found only at the Andamooka Opal field in South Australia. It consists of a fine grained limestone rock with opal ingrained in this limestone matrix. The opal can exist in all sorts of patterns. Because of the...

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Opal Formation -An Alternative Theory

21 November 2019 by Johno

A little while ago "Mac" contacted me with his theory on opal formation. I have my theory on this topic but it is good to keep an open mind as none of us were around when opal was formed. Mac has given me permission to present his thoughts on...

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Opals for Sale

20 October 2019 by Johno

A friend in Ballina, who's father owned a mine at Andamooka many years ago, has reached the stage in his life where he wants to sell off his collection of opal. I have agreed to put some of them on this website to see if anyone out there is interested....

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How Was Australian Precious Opal Formed

21 January 2019 by Johno

How was Australian Precious Opal Formed. I have read many many different articles on how Australian precious opal was formed but have had some doubts on the commonly accepted theory of water seeping through sandstone and dissolving silica ,which then formed a gel and seeped into cracks and crevices...

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Some More Andamooka Matrix Opal

24 May 2017 by Johno

Andamooka Matrix Opal Recently Ross from NSW contacted me and asked if I could treat some Andamooka Matrix Opal his father had found some time ago, when he mined at Andamooka. Ross apparently has quite a collection of Andamooka Matrix opal and is looking to sell it. If anyone...

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Crystal Opal - The Worlds most beautiful opal

24 December 2016 by Johno

Crystal Opal Crystal opal is so named because you can see right through it when you hold it up against a bright light. You can't see any of the colour play when you do this but let the light reflect off a good crystal opal and you will see...

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Queensland Boulder Opal

23 October 2016 by Johno

Boulder Opal Boulder opal is a special form of opal found only in Queensland. "Boulder opal" is the result of opal forming silica penetrating cracks and crevices in ironstone boulders. Formed millions of years ago, amorphous silica seeped into random cracks or in between concentric layers of ironstone...

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Australian Opal - World's Best

6 March 2016 by Johno

Australian Opal Ausralian Opal is arguably the most beautiful and stable opal in the world. It is an amorphous form of Silica with a water content varying from 3 percent to 21 percent but usually within the range of 5-10 percent. Amorphous is defined as "without any clearly defined...

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Lightning Ridge Fossils

2 January 2016 by Johno

Lightning Ridge Opal Field Lightning Ridge Fossils are among some of the most amazing fossils found any where in the world. At Lightning Ridge opal is usually found near the interface of the Wallangulla sandstone and the Finch clay facies (called the opal dirt). The opal is found...

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Opalised Fossil photographs

17 November 2015 by Johno

I am sorry to have to delete the content of this post. Andre has instructed me to remove all of his photographs. Johno...

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The Desert Sea Collection of Opals - Stolen

10 November 2015 by Johno

The Desert Sea Collection The Comfort Inn Experience Motel at Coober Pedy is famous for it's owners great collection of opalised sea shells known as" The Desert Sea Collection". In March 2014, Andre was in Coober Pedy and was shown this collection. He also photographed the Desert Sea...

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More Andamooka Matrix Opal

5 November 2015 by Johno

Andamooka Matrix Opal Andamooka matrix opal is still a much maligned form of opal in many people's minds. The fact that it is a treated form of opal seems to ignore the fact that it is still basically one of natures treasures with it's beauty enhanced by changing the...

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Opalised Fossils You Must Not Miss

1 November 2015 by Johno

Opalised Fossils Opalised fossils are one of natures greatest treasures. Opal can hide many surprises. Because opal was generally formed at the bottom of the sea or swamp, it has replaced many interesting things. Sea shells, fresh water shells, sea creatures, bones and plants have all been found transformed...

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Andamooka Rainbow Matrix Opal

5 May 2015 by Johno

Andamooka Rainbow Matrix Opal is fast becoming popular with those who can't afford a "Real Opal". Originally it was called "concrete" because that was what it looked like although you could see small specks of opal in amongst the concrete like grains. It is a porous quartzite host rock...

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More Andamooka Matrix Opal

6 October 2014 by Johno

More Andamooka Matrix Opal During the last month I was contacted by Andre who told me he had a couple of pieces of Andamooka matrix opal he had collected some time ago. He purchased one of these from Cash Converters and they were part of a deceased estate. Andre...

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Crystal Opal

4 August 2014 by Johno

Opal is a form of silica which has water molecules attached to it (varying from 3% to 21%) and is called hydrated silica. It is an amorphous material, which means that it does not have a crystalline structure. It's internal molecular structure can be ordered. Opal consists at a micro...

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Amazing Patterns in Gemstones

27 May 2013 by Johno

Whenever we think of opal we usually think of gems used in jewellery, but there are some opals and other gemstones which portray beautiful and intriguing patterns, but which are not necessarily suitable for use as jewellery. Some of the stones shown below are from my collection and while...

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Andamooka Opal - Painted Ladies

30 April 2013 by Johno

Opal at Andamooka is found in a narrow band of depths varying up to 600 mm. In this bed there are many boulders of strongly bonded quartzite of varying sizes.,Today, as you wander among the great piles of disturbed overburden which is mixed with the old opal level , you...

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Opalised Shells

30 April 2013 by Johno

The opal fields of Australia were formed at the bottom of a large inland sea. In this sea there were all sorts of marine creatures including turtles, crocodiles, dinosaurs, all sorts of fish and of course shellfish. As these creatures died their bodies sank to the bottom of the sea...

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Yowah Nuts - Found only at Yowah Queensland

14 February 2013 by Johno

Yowah is a small outback opal town in Queensland located about 1,000 km west of Brisbane and about 130 km west of Cunnamulla.There is a sealed road all the way so it is very easily accessible. The opal field surrounding Yowah is quite small, being about 4 square kilometres. It...

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Cutting Opal - Doublets

13 February 2013 by Johno

If you have any thin pieces of opal with nice colour but believe it is too thin to cut a cabechon then think about making a doublet. A doublet is basically a fairly thin layer of usually opal glued to a thicker layer of opal potch or some other...

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Buying Opal

23 January 2013 by Johno

For all of us amateur opal cutters getting a regular supply of reasonable quality is one of the major problems. As opal mining slows down due to rising costs and lack of new finds, it is getting harder and harder to access. I have been lucky living in Australia...

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Andamooka Matrix Opal

17 January 2013 by Johno

The term matrix opal refers to a type of opal where there is a base stone with tiny pieces of brilliant opal interspersed within this base stone. The base can be limestone, sandstone or even ironstone. At Andamooka and apparently nowhere else in the world, two types of matrix opal...

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Treating Andamooka Matrix Opal

15 November 2010 by Johno

Andamooka matrix opal is basically a limestone base rock impregnated with tiny pieces of precious opal. Because the limestone is very pale it is often difficult to see the play of opal colour in the stone and hence a method of darkening the limestone background was developed so the colour...

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