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 Post subject: New objective, new photos
PostPosted: Thu Jan 16, 2020 11:39 pm 
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I recently got my hands on a nice Nikon 20x planapo objective, and I've been having fun taking some photos with it. It has very limited working distance so lighting is a real challenge, but it does take nice pictures when everything lines up.
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A metallic inclusion in a golden beryl from Madagascar. The crystal is just under 0.2 mm across.
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This stone is also full of flattened two-phase inclusions in negative crystals. These, along with flat hematite inclusions perpendicular to the C-axis give the stone a beautiful golden sheen.
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Moving on to another beryl, we see these complex skeletal crystals of hematite/ilmenite. When they're sufficiently dense they can produce a black beryl with a 6-ray star, but when scattered they only give a spangled sparkle.
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Not an amazing photo, but I really like how this fracture in a faceted amethyst reflects the underlying Brazil Law twinning of the quartz.
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Also not really an impressive photo, but these little negative crystals are about 0.01mm across, which is kind of cool.
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Imaging through agate is a challenge at any scale but this one turned out kind of neat.. This pseudo-twig mineral structure is a pretty commonly-seen feature in agates. It's easy to see how olde tymie scientists imagined there was a mineral parallel to the plant kingdom.

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 Post subject: Re: New objective, new photos
PostPosted: Sat Jan 18, 2020 12:52 pm 
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These pics are great!
Start thinking about a holiday calendar for 2021.


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 Post subject: Re: New objective, new photos
PostPosted: Sun Jan 19, 2020 5:55 am 
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Beautiful pictures. Thanks much for sharing.


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 Post subject: Re: New objective, new photos
PostPosted: Mon Jan 20, 2020 2:14 am 
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Thanks! I'm still working on this one (and need to get it on a more suitable setup) but it's been a lot of fun to experiment with.
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More hematite in beryl--the skeletal hematites form perpendicular to the C axis, but parallel to the prismatic faces you get these flat platelets, with their long axis parallel to the C. These show a nice range of colors, most likely controlled by thickness, but perhaps by iron vs titanium content.
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Just a super tiny little crystal (~0.05mm) floating in a tumbled sample of blue dumortierite in quartz (not the nice clear quartz with prismatic crystals from Brazil, the blended stuff). I'm not sure what it is but it has a very classic crystal form.
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Little black specks in Ethiopian opal! You've likely seen closeups showing beautiful pyrite cubes and dendrites, but apparently they're sometimes...these things. Little spikeballs? Some sort of oxide or sulfide? Who knows, but they look kind of cool anyway. Some at least look like they'd show a more classic dendritic form from the right angle.
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Something to look out for this Tucson is resin filled aqua. I saw quite a bit of it last Tucson and nobody I asked disclosed any treatment (one guy said the Chinese put a special oil on to polish the surface which is, uh, really something). I gave a sample to the GIA who wrote up a lab report on it in the Summer issue (https://www.gia.edu/gems-gemology/summe ... Epyewvafdo). All the rough stones I saw could be very easily identified by an obvious glassy coating, unnatural color and generally wrong look, but one thing that spooked me a bit was that I didn't spot any bubbles through a sawn and polished surface with my gemscope. It was only witha compound objective that I could see any, but they are tiny! The average bubble is around .01mm. I suspect a cut stone without the unnaturally colored dye could be difficult to spot, and it's hard to imagine they'd stop at just making cheap trinkets with this technique.

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 Post subject: Re: New objective, new photos
PostPosted: Mon Jan 20, 2020 2:56 am 
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These photos are fantastic. Thank you so much for sharing them!


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 Post subject: Re: New objective, new photos
PostPosted: Mon Jan 20, 2020 11:47 am 
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These days in all stones, if it has a fracture they are filling it. Be on guard.


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 Post subject: Re: New objective, new photos
PostPosted: Mon Jan 27, 2020 1:27 am 
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More!
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A little transparent golden crystal (probably biotite?) floating in Ethiopian emerald.
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Layered pyramids of rutile floating inside this spinel.
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A couple more scenes in the same spinel, I love how iridescent they are at the right angle.
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A metallic inclusion inside one of my dad's sapphires--I'm guessing biotite from the hints of hexagonal structure it shows.
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A transparent inclusion (apatite?) floating in sapphire, with a little spot of blue diffraction at the interface between them at the back of the crystal.
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Not a very original subject, but I do really like the look of hematite inclusions in a golden star sapphire. It's amazing they're organized enough to produce a sharp six ray star.

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