Joined: Sun Oct 16, 2005 12:22 pm Posts: 21602 Location: San Francisco
Sunset quartz was discovered in 2006 in Minas Gerais, Brazil. It was in very limited supply, with the vein producing only 5 kg. of gem quality material total. Yesterday, Karim paid me a visit and had a tremendous personal collection of Sunset Quartz that I would like to share with you.
The yellowish and orange color of the quartz is the result of microscopic acicular (needle-like) inclusions. Analysis of these inclusions, reported in Gems & Gemology in Winter 2006, determined that they were NOT rutile as we might have suspected but were composed of Si, Al and Fe with traces of K! The identification of the actual mineral was inconclusive. The material is semi-transparent to translucent with a milky consistency. The RI, Birefringence, SG is typical of quartz.
Joined: Tue Jun 03, 2008 4:40 pm Posts: 2667 Location: South Dakota
Wow nice stuff..it's just like rose quartz but a different color..translucent..needle-like inclusions..etc. Nice stuff. So it's pretty rare with only 5kg of stuff..glad you got a hold of some to take pics, barbra! Did you get to keep any?
_________________ MrAmethystguy ~ Some jokes just fluorite over my head!
Joined: Sun Oct 16, 2005 12:22 pm Posts: 21602 Location: San Francisco
Bear Williams- SGL wrote:
Hi Barbra,
Neat looking material, I'm wondering if the inclusions could be that of limonite?
___ bear
That would make sense, Bear, especially considering the story in the latest G&G about how inclusions misidentified in Brazilian topaz as rutile needles have been subsequently identified as acicular limonite.
But, I'm not personally determining that these inclusions were unidentifiable, I copied it from the 2006 G&G article.
Joined: Sun Oct 16, 2005 12:22 pm Posts: 21602 Location: San Francisco
amethystguy wrote:
Wow nice stuff..it's just like rose quartz but a different color..translucent..needle-like inclusions..etc. Nice stuff. So it's pretty rare with only 5kg of stuff..glad you got a hold of some to take pics, barbra! Did you get to keep any?
Yes, I did get to keep one....
It weighs 1.68 carat and it is the host of the inclusions I pictured above.
Joined: Sun Oct 16, 2005 12:22 pm Posts: 21602 Location: San Francisco
The GIA described the diaphaneity as semi-transparent or milky... I think we'd all agree with that.
The gem has already been given a prominent new home on my orange tray, next to my East African Illusion Sunstone.
Joined: Mon Oct 17, 2005 2:39 pm Posts: 3528 Location: San Francisco Bay Area, CA
Here's a shot through a 20x Belomo loupe. You can make out some of the accicular inclusions as well as another "weird" inclusion. This is the largest trillian in my photo. The plane on the weird inclusion is about 45 degrees out from the photo... the right end is closer and the left end is farther.
Joined: Mon Oct 17, 2005 2:39 pm Posts: 3528 Location: San Francisco Bay Area, CA
Just a note to add to Barbra's description of the chemical composition of the inclusions. G&G notes that the Si content of the inclusions was LESS than in the surrounding quartz.
Joined: Mon May 14, 2007 11:00 am Posts: 1133 Location: Monterey, CA
gem-n00b wrote:
Just a note to add to Barbra's description of the chemical composition of the inclusions. G&G notes that the Si content of the inclusions was LESS than in the surrounding quartz.
Perhaps this belongs in the Gem Quiz section.
The silicon content of quartz is 50%. Can anyone name any other gem material (aside from synthetic moissanite) that doesn't have a silicon content of LESS than quartz?
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