Welcome to the Rock Tumbling Hobby Forum where we share a love of rocks and a sense of community as enduring as the stones we polish.
The RTH Forum of www.RockTumbling.com is an Amazon Associate site and we earn money from
qualifying purchases you make after clicking on our links such as this
Rock Tumbling Supplies on Amazon
link for instance, or any of our various product ads and banners. By clicking our links every time you begin your Amazon shopping
experience, you are generating a bit of revenue for the forum which helps us cover our expenses. Thank you for your support!
If you cannot see Amazon ad banners directly below this text, please whitelist this site in your ad blocker(s). The ads below have been hand-selected for relevant content, and your patronage directly benefits this forum community, thanks!
In the 1980s I was working in PNG off the northern coast of Australia, a couple of the crew got involved with opals, so I got some and use there equipment. We did not have a clue what we were doing, but these now reside in a jar. Always meant to do more with them but so far have not. I do like to take them out and look at them from time to time.
You have some very nice preforms there. A little TLC is all that's needed to turn some of them into gems. If you need help/advice let me know. I've specialized in opal-cutting for over 50 years. Do you know which fields they're from? Most look like light opals from Andamooka/Coober Pedy but a few could be dark/black opals from Mintabie vertical veins or Lighting Ridge. Nice stuff!
You have some very nice preforms there. A little TLC is all that's needed to turn some of them into gems. If you need help/advice let me know. I've specialized in opal-cutting for over 50 years. Do you know which fields they're from? Most look like light opals from Andamooka/Coober Pedy but a few could be dark/black opals from Mintabie vertical veins or Lighting Ridge. Nice stuff!
Some of it, I recall, was from Cooper Pedy and Mintabie.
[quote author="woodman" Some of it, I recall, was from Cooper Pedy and Mintabie. [/quote]
Yes, the light opal is typical of Coober Pedy and the dark ones look like most of the Mintabie black seam opal I've cut. The Mintabie seams are sort've like an opal "sandwich" with black potch on both sides and color (if any) in the middle. It's always a tough decision about which side to start grinding from. Sometimes the black potch shows through the top as thread-like or blotchy inclusions like a couple of your stones.
[quote author="woodman" Some of it, I recall, was from Cooper Pedy and Mintabie.
Yes, the light opal is typical of Coober Pedy and the dark ones look like most of the Mintabie black seam opal I've cut. The Mintabie seams are sort've like an opal "sandwich" with black potch on both sides and color (if any) in the middle. It's always a tough decision about which side to start grinding from. Sometimes the black potch shows through the top as thread-like or blotchy inclusions like a couple of your stones. [/quote]
Yes, with my limited knowledge, I had problems with which side to polish. on some of them I polished both sides. I am finding that it is very hard to get good pictures of them showing true color. Would it be better to try natural sunlight rather than flash?
Precious opal is fairly difficult to photograph. I get my best still shots using clear incandescent overhead bulbs with the camera's white balance adjusted for that type of lighting. They show some reflections of the bulbs but with care that can be minimized. I've found that using any kind of diffused light kills the opal's light show.
I've seen some excellent videos with the opals set on a rotating platform so their full play of color is exhibited. I have everything I need -- except time -- to experiment with that technique. I'm not sure what kind of lighting is used.
Post by spiritstone on Feb 16, 2015 13:16:55 GMT -5
I find them hard to photograph to. Best way I found is to play with the lighting until you can find the same match of POC colors in the cam display screen, as to what you would see with your eyes if the stone was in your hand. Some opal like it really bright while some can give you just as big of a show in dimmer light conditions. I hope that helps you somewhat. I took this one in direct sunlight and just turned down the brightness setting until i could see the colors. White base opal is the hardest to photograph.
Last Edit: Feb 16, 2015 13:29:13 GMT -5 by spiritstone
because as we know, there are known knowns; there are things we know we know. We also know there are known unknowns; that is to say we know there are some things we do not know. But there are also unknown unknowns -- the ones we don't know we don't know.
Very pretty opals, woodman, and sure looks like you and your coworkers had a good eye for finding some nice ones! Hope you'll cab them.
I cannot take pics of opals, but I found I can take better pics of them in low lighting conditions. ?? Many thanks for the photography tips, spiritstone and gemfeller.
[quote author="gingerkid" Dang, gemfeller, beautiful opals but this one is just 'WoW!!' [/quote]
Thanks Gingerkid. That stone's from the best and brightest parcel of opal rough I've ever bought. It tends to be slightly directional but the number and intensity of colors will make a top-end pendant one day. I personally think Mintabie has produced some of the finest Australian opal, mainly ultra-bright multicolored crystal like that stone. I ran across a 5-6 oz. parcel of similar rough some time back and was ready to mortgage the house to buy it. My wife had a different opinion however so I ended up without it. It beat any opal I've ever seen except a few rare red-on-blacks "with the blue" from Lightning Ridge.
This space is for temporary chat only and all posts drop off automatically and are not saved.
Members with real questions or comments that need an actual response, please post on the main forum - not here! Casual PG-13 posts only, no politics or religion please!
rocknrob: That was one heck of a windstorm that thankfully missed me. I guess Seatac almost hit 60mph gusts. I bet those were some fun landings
Nov 20, 2024 21:55:16 GMT -5
rocknrob: I'll always love my pet rock, he's such a geode boy.
Nov 22, 2024 9:27:33 GMT -5
Welcome to the Rock Tumbling Hobby Forum where we share a love of rocks and a sense of community as enduring as the stones we polish.
The RTH Forum of www.RockTumbling.com is an Amazon Associate site and we earn money from
qualifying purchases you make after clicking on our links such as this
Rock Tumbling Supplies on Amazon
link for instance, or any of our various product ads and banners. By clicking our links every time you begin your Amazon shopping
experience, you are generating a bit of revenue for the forum which helps us cover our expenses. Thank you for your support!
