MSW1223: Large Corundum var. Ruby - Unique Tabular Ruby Cluster from China

Description

Fluorescent Mineral Sales MinerShop
Corundum var. Ruby - Unique Tabular Ruby Cluster
Guangxi, Zhuang Automomous Region, China
2 1/2” x 1 1/2" x 1”, 1.7 oz
This cluster of hundreds (or thousands) of intersecting tabular ruby crystals screams color and brightness, with a delicate, very unusual crystal habit. We have had EDS and spectrograph testing on the ruby crystals and part of the matrix, as well as observation by numerous folks much more knowledgeable; the consensus is amazing clusters of corundum var. ruby on an unknown matrix and of unknown origin. (General information below auction pics).
Winning bidder: Make sure to right-click and print (or save) ID card located below for your records
Mineral in image above shown under Longwave UV
Mineral in image above shown under Shortwave UV light
Dollar bill showing size of mineral
Macro of crystals under longwave UV (365nm)
Macro of crystals under natural lighting (365nm)
These pieces were found at the 2018 Tucson Gem show. A vendor had them sitting on her table in one of the tents behind a hotel. She had no clue what they were. Under the 365nm Convoy flashlight they fluoresced brightly. But when looking closely at the thin tabular crystal habit, a ruby ID couldn't be correct; rubies simply are not commonly seen in this thin, platy habit (although the hexagonal shape made sense, and there are certainly micro-photos of such a habit). We spent the rest of the show trying to find other examples with no success. Showed them to every knowledgeable person/geologist and got the same reaction - nice ruby color, but can’t be. Several folks made guesses (erythrite being a top one).
It was easy to eliminate the erythrite guess made by some of the geologists using a hardness test. Erythrite is a very soft mineral. These crystals are hard and brittle. We isolated a few and crushed them against a piece of glass; they scratched the glass handily; a needle under the microscope had no effect and in fact showed that the crystals were quite hard and firm, although delicate because they are so thin. Did some research on the web and came up empty. That exhausted our ID methods. A small specimen was sent to some folks in Europe for real testing. The results were shocking - Thin, flat corundum crystals, var. ruby.
A spectroscopic examination clearly shows the luminescence matches that of corundum. The transmission spectrum shows the typical green and blue absorption bands for Ruby. But the specimen fluoresces under a halogen lamp and you see an emission spectrum present in the transmission one. The absorption in the blue is somewhat stronger than in ruby (presence of Fe3+ or Ti3+), resulting in a more purple color. Ruby from Chumar (Nepal) has a similar purple color. It is generally accepted that any corundum with a pink, red, or purple coloration is ruby.
A personal note from Mark Cole, MinerShop
"As many of my followers have noticed, I (Mark) have retired from active sales. My daughter, Valerie, has joined the MinerShop crew and will be taking over our sales. She has assumed my large inventory of Greenland and other world-wide minerals, has learned to take the same great photos you've come to expect, and will offer the same great service you've gotten used to. She grew up around these minerals and, thankfully, got the glow-bug herself at a young age. A father's dream to have one of his children appreciate our hobby, insuring a home for his lifetime's passion. Please support her in this transition, and be assured I'm behind her every step of the way."
Shipping and Other Information
All packages will be shipped via USPS Priority Mail.
International customs fees, import duties and restrictions are the responsibility of the buyer.
Pictures and Representations:
Specimen colors reproduced as accurately as my camera and monitor allow (and are subject to the way your monitor displays colors). Sizes are approximate.
Please use dollar bill behind specimen and actual measurements to form a mental picture of the size.
Measurements show the widest dimension of each side.
Some images may be enlarged to show detail. Refer to sizing pic for proportional size
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