New star sapphire crystal

Starguy
driving up their electric bill

Member since January 2014
Posts: 2,580

New star sapphire crystal Mar 31, 2021 22:15:57 GMT -5 RWA3006, rockjunquie, and 9 more like this

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Post by Starguy on Mar 31, 2021 22:15:57 GMT -5

This one shows good prospects for showing a star. gemfeller you can see some good zonation on the cross section.

I think I nearly have the market cornered on these things. If I were to guess, I’d say I have 40 pounds. The biggest one is 3.5 lbs. When I was a young man in the early 1980s, I found a guy selling them at Quartzite GIA. The next year, he reminded me that I bought them all the previous year. If you want me to explain how to identify star sapphire let me know. Star garnet and star rose quartz are tougher but you can tell them too. Sometimes the origin is the best clue. I’ll post photos once I get an end polished. I think I got a Verneuili process created boule today too. It will be a ruby.

Last Edit: Mar 31, 2021 22:46:13 GMT -5 by Starguy

Brent

gemfeller
Cave Dweller

Member since June 2011
Posts: 4,060

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New star sapphire crystal Apr 1, 2021 0:51:32 GMT -5 rockjunquie, Starguy, and 2 more like this

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Post by gemfeller on Apr 1, 2021 0:51:32 GMT -5

Big crystal Brent! If your question is whether a given corundum crystal will "star," I use a high viscosity commercial preparation called Star Refractol, which isn't being sold any longer. A tiny drop on the end of a crystal will usually show a tiny star in strong light -- if the material will "star." It works pretty well as an indicator of asterism in many materials.

A substitute for it is benzyl benzoate which is available reasonably here: texlabsupply.com/chemicals-and-solvents/benzyl-benzoate-nf-fcc-usp/

Don't use this stuff around plastic. It will destroy some types on contact -- don't ask me how I know this! Other high viscosity materials like STP or even honey are said to work too but I haven't tried them.

I don't think zoning in corundum is a sign of asterism. In fact it's a negative in quality gem material where zero inculsions (other than "silk") are the goal. But it's proof of natural corundum if lines are straight and properly angled as in your specimen, and not curved as in lab-grown flame-fusion corundum.

Happy cutting -- and be sure to post images of your finished stones.

RWA3006 Cave Dweller Member since March 2009 Posts: 4,633	New star sapphire crystal Apr 1, 2021 6:52:34 GMT -5 Starguy likes this Quote Select Post Deselect Post Link to Post Member Give Gift Back to Top Post by RWA3006 on Apr 1, 2021 6:52:34 GMT -5 I look forward to seeing how this develops.
	If we were able to carry the love and tolerance shown here into the world as a whole and get anyone to follow the example set, who knows what could be born from that? Stonemon RIP

miket misunderstood rock expert Member since April 2018 Posts: 11,239	New star sapphire crystal Apr 1, 2021 9:44:14 GMT -5 Starguy likes this Quote Select Post Deselect Post Link to Post Member Give Gift Back to Top Post by miket on Apr 1, 2021 9:44:14 GMT -5 It's been a while since you've posted these, Brent...can't wait to see how it turns out!
	Too much walking shoes worn thin Too much trippin' and my soul's worn thin _______________________________ Weight of my heart, not the size

rockjunquie Global Moderator Member since March 2012 Posts: 34,990	New star sapphire crystal Apr 1, 2021 12:09:07 GMT -5 Quote Select Post Deselect Post Link to Post Member Give Gift Back to Top Post by rockjunquie on Apr 1, 2021 12:09:07 GMT -5 Can't wait to see if you're right. Too cool!

Post by Starguy on Mar 31, 2021 22:15:57 GMT -5

Post by gemfeller on Apr 1, 2021 0:51:32 GMT -5

Post by RWA3006 on Apr 1, 2021 6:52:34 GMT -5

Post by miket on Apr 1, 2021 9:44:14 GMT -5

Post by rockjunquie on Apr 1, 2021 12:09:07 GMT -5

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