More Andamooka Matrix Opal
6 October 2014 by Johno
Categories: Opal Types | Opal Treatments | Australian Opal
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 was obviously quite astute as the Andamooka matrix opal was not treated. Unless you know what you are looking for, some untreated Andamooka matrix opal can be quite un-exciting (if there is such a word). It is usually very pale with only a hint of colour in it. However if it is treated by heating it in a sugar solution for several hours and in a sulphuric acid solution the background turns black as the acid combines with the sugar in the pores of the stone to form carbon. This change of background allows the opal colours to really stand out. It is a really amazing transformation and the end result can be a gemstone of great beauty. Andre treated the Andamooka matrix opal with sugar and battery acid. Most people insist you need 98% sulphuric acid but these results show that this is not necessarily the case always although Andre now advises that the battery acid started boiling in his wall oven and in the end it was destroyed. Might be better to stick with the 98% acid and cook it in a well ventilated area. I use an old electric fry-pan and a pyrex dish and this works well.
If you are interested in the treatment of Andamooka matrix opal there are other posts on this website showing you how and giving a few tips.
Unfortunately some people don't like Andamooka matrix opal because it has been treated. I believe this is unwarranted because the opal itself has not been changed. It is only the surrounding material that has been darkened thus releasing the great beauty of this gemstone. Andre has allowed me to show you the two beautiful stones he was able to obtain. One he has treated himself and this is shown below. It is approximately 700 carats and is absolutely beautiful. Judge for yourself.
An amazing Andamooka Matrix Opal
Beautiful Treated Andamooka Matrix Opal
Isn't it an beautiful gemstone?
Below is another photograph of the same stone.
Another view of a treated Andamooka matrix opal
The colours are very strong and intense and it certainly looks as if the stone has polished beautifully. Some Andamooka matrix opal, if it is too porous will not take a high polish and it is necessary to coat it with liquid glass to enhance the colour and brightness.
Carved Peacock Opal
The other stone that Andre obtained was carved for a friend of his about 25 years ago. He bought it from the son of his friend when his friend passed away. It is in the form of a peacock. The result is a superb collectable item. The person who carved it had exceptional talent. I have attempted very basic opal carving and it is very difficult. Again judge for yourself this great work of art.
Carved Peacock Andamooka Matrix Opal
The carving is 25 cm by 20 cm and the detail is superb.
This next photograph is the back of the Peacock.
I would like to thank Andre for allowing me to show you these fine examples of Andamooka matrix opal and other opal he has collected. For most of us amateur opal buffs it is very difficult to find and purchase beautiful gemstones. They are getting rarer and rarer and are usually very costly. Andre was very fortunate to find these stones in a cash converter and get them for a good price. He also buys rough from Gem Shows and wherever else he can find them. It just shows that if you keep your eyes open you never know what you will find.
Yowah Nut Pair
Andre has updated me in August 2015 following a trip to Yowah Opal Field where he purchased some nice yowah nuts.
A split Yowah nut pair
This first picture shows the great beauty of these nuts.
Opalised Bone
Opalised bone with plant stem
This photo is the end of an opalised bone. The line in the middle is not a crack. It is an internal ice like layer that crystallized in the warm and humid conditions in the cavity of the hollow bone and then another layer of opal formed above it. It also appears to have a plant stem in it. It is mind boggling how this all formed many millions of years ago. Thank you Andre for sharing this with us. The photo below clearly shows the plant stem within the opal
Opal with Plant stem
Andre has also placed a lot of photographs of his opal collection on You Tube. You can look these up on Opal Fever. Andre has also started a new blog site where you can see photographs of his large and unique opal collection. Click on the link Opal Collection of Andre to see these photographs.
Johno