Joined: Sun Oct 16, 2005 12:22 pm Posts: 21602 Location: San Francisco
I went to the San Mateo Gem Show today and found my favorite dealer for gem beads. As usual, he (Kit owner of Gem House USA, Inc) had some truly unusual gem beads. He showed me a strand of color change garnet beads. I bought a strand, a little stretch, not inexpensive....but worth it. Standard gemological instruments: Refractometer: 1.78 Polariscope: ADR Gemmoraman: Paralspite: Red Spessartite
Rare earth magnet picks up individual beads. Some pics: 1. liquid feathers, intersecting rutile needles at 90º (trust me) and apatite xls. Some inclusions, I can't identify. 2. Rutile needles 3. Backlit: bug juice 4. Incandescent light...generated by an option on my camera, proved unreliable. The beads still looked bug juice. 5. On my kitchen counter in a sunbeam. Raspberry. That is still accurate.....although I now believe some of my incandescent dining room light tainted my findings.
Post subject: Re: Unusual (reverse?) color change pyralspite beads
Posted: Sun Mar 18, 2018 12:06 am
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Joined: Sun Oct 16, 2005 12:22 pm Posts: 21602 Location: San Francisco
What a difference a day makes. I unstrung all my beads to restring them with some silver beads and a clasp on transparent steel reinforced cord. (holes are too small to properly string on silk)
I was in my incandescently lit dining room and all the loose beads looked raspberry.
The only difference with the beads was the removal of the red cord they were originally strung on. Hit the cord with a UV light and it glowed electric hot pink.
Ok, starting from the beginning. Corrections. Refractive Index: 1.78 (yesterday I used 1.78 RI liquid; today 1.81) Magnetic Response: Rare earth magnet picks up individual beads....the strand doesn't move.
Color change YES, Reverse color change:NO. A handful of beads in the dining room:
The same group lit with a fluorescent back light:
Long story short, Stefan tell Dr. Schmetzer, "Nevermind"
I took my leftover loose beads down to the lab. One bead had a honeycomb like inclusion:
so high in spessartite with some Goldmanite, Uvarovite and Pyrop...
But you love bug juice colors!!
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Unfortunately so many use LED to demonstrate a fine blue or more dramatic CC in some spinel or blue sapphire or LW UV to show the quality of pink, orangepink etc. spinel or corundum - course they all fluorescence like crazy - need a lot of iron to quench it.
So exact light source is really important to know...
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