Forums
New posts
Search forums
What's new
New posts
Latest activity
Members
Registered members
Current visitors
Charts
Log in
Register
What's new
Search
Search
Search titles only
By:
New posts
Search forums
Menu
Log in
Register
Install the app
Install
Gemstones, Minerals & Fossils
Gemstones and Minerals
❓Your Mineral Identification Questions answered here
JavaScript is disabled. For a better experience, please enable JavaScript in your browser before proceeding.
You are using an out of date browser. It may not display this or other websites correctly.
You should upgrade or use an
alternative browser
.
Reply to thread
Help Support Prospecting Australia:
This site may earn a commission from merchant affiliate links, including eBay, Amazon, and others.
Message
<blockquote data-quote="user 4386" data-source="post: 653085" data-attributes="member: 4386"><p>I think a number of fields. Most fields in Queensland (but they are dominantly boulder opal fields although vainlets occur in the same fields). Andamooka comes to mind in South Australia. It often invades the spaces between the sand grains and atb Andamooka is sold as "matrix opal" for aquariums etc (yours is an actual vein of course, but veins also occur there in sandstone). Since it is not really being sold as a gemstone for aquariums. they usually soak it in sugar solution, then acid that turns the sugar to black carbon enhancing the colour. This is what tends to occur naturally in black opal, where the black is actually a black material between the spheres that make up opal. </p><p></p><p>I don't think colours are diagnostic of any opal field. Precious opal does not have any colour in it of course. It consists of packed spheres of varying diameter that break up light passing through the opal in the way a prism or rainbow does. Patches with different diameter spheres refract light by different amounts giving different colours - there is no actual colour in precious opal. Makes it rather magical!</p><p></p><p>Opal looks like this under an electron microscope.</p><p></p><p>[ATTACH=full]4565[/ATTACH]</p></blockquote><p></p>
[QUOTE="user 4386, post: 653085, member: 4386"] I think a number of fields. Most fields in Queensland (but they are dominantly boulder opal fields although vainlets occur in the same fields). Andamooka comes to mind in South Australia. It often invades the spaces between the sand grains and atb Andamooka is sold as "matrix opal" for aquariums etc (yours is an actual vein of course, but veins also occur there in sandstone). Since it is not really being sold as a gemstone for aquariums. they usually soak it in sugar solution, then acid that turns the sugar to black carbon enhancing the colour. This is what tends to occur naturally in black opal, where the black is actually a black material between the spheres that make up opal. I don't think colours are diagnostic of any opal field. Precious opal does not have any colour in it of course. It consists of packed spheres of varying diameter that break up light passing through the opal in the way a prism or rainbow does. Patches with different diameter spheres refract light by different amounts giving different colours - there is no actual colour in precious opal. Makes it rather magical! Opal looks like this under an electron microscope. [ATTACH type="full"]4565[/ATTACH] [/QUOTE]
Verification
Post reply
Gemstones, Minerals & Fossils
Gemstones and Minerals
❓Your Mineral Identification Questions answered here
Top