rockhoundoz
starting to spend too much on rocks
Member since March 2017
Posts: 131
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Post by rockhoundoz on Jan 17, 2019 18:15:13 GMT -5
Thanks for the updates. The different angles, light and backgrounds sure make a difference. Yeah, that's very true & also it's quite a challenge to get the conditions right for a picture to actually resemble the stones in person! I'm not actually sure if this picture is different enough to warrant posting, but it looks closer to an accurate color. Still low light near sunset, but slightly better.
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gemfeller
Cave Dweller
Member since June 2011
Posts: 3,767
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Post by gemfeller on Jan 17, 2019 18:25:45 GMT -5
My only suggestions at this point:
American Gemological Laboratories 580 5th Ave Suite 706, New York, NY 10036
Gemological Institute of America 50 W 47th St #800, 8th floor, New York, NY 10036
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Post by stephan on Jan 18, 2019 0:17:18 GMT -5
Also, what's the best/easy best 😅 neutral background for pictures of this kind ? The colors usually considered "neutral" are white, gray, beige and black. For gem photography purposes you just have to avoid backgrounds that influence the hue of the stone being photographed by reflection. For instance, I photograph a lot of transparent faceted gems. I couldn't figure out why I was picking up unnatural tints in my pictures until I realized the color of the shirt I was wearing or other main colors in the room were being reflected from the subject stones. The test of color change in gems is the color in daylight vs. the color in incandescent (tungsten) light. A color change gem like Alexandrite will show a complete hue change, from blue/green in daylight to purplish-red in incandescent light. Stones that exhibit so-called "color-shift" may show variations of a single hue in different lighting conditions. For instance, tourmaline from some sources appears strongly pink-red in daylight but shifts to orangy-pink under tungsten. ETA: R2D's comment about correcting white balance is very important. Each camera has a different system for those adjustments, check your manual. Oddly enough, with the way camera sensor work, grass-green is also a neutral color, of sorts -- at least as far as white balance is concerned.
For the white balance, most cameras will let you select from sunny daylight, shade, cloudy daylight, tungsten and fluorescent lighting (in some of the modes) to at least get the white balance close.
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Post by greig on Jan 18, 2019 14:42:12 GMT -5
Any chance you can walk uphill, upstream or up glacier to try to find the source? You might just have a spot nearby for some great collecting.
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swaver101
starting to spend too much on rocks
Whoops
Member since May 2018
Posts: 111
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Post by swaver101 on Jan 19, 2019 6:27:39 GMT -5
Beautiful stuff! If I Had to guess I'd say some kind of Agate.. but I just guess for fun
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rockhoundoz
starting to spend too much on rocks
Member since March 2017
Posts: 131
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Post by rockhoundoz on Jan 19, 2019 16:29:37 GMT -5
Any chance you can walk uphill, upstream or up glacier to try to find the source? You might just have a spot nearby for some great collecting. Indeed, I tracked the occurence pretty far upstream & still have some public land above to continue 👍. It's a really old/eroded geology around here though, so I'm not even certain there'd be any in-situ outcropping left. May all just be eroded out in the gravel already. We also have deep soil, so if there is a vein etc, could be deeply buried. Thanks for the extra tips Stephan! Yeah, I often use the green grass for photographing my agate/jasper etc, but thought this blue/transparent stuff might be too influenced by green. Also, I did discover the WB features on my phone, & experimented with it in those last couple of photos in order to achieve a more accurate color : ). Gemfeller, ultimately I think I will submit a sample to GIA. Thanks for the info! $70 for quartz ID, so I think it's worthwhile. & to Swaver101, yes, ultimately my guess is chalcedony as well. However, given that, I have collected a few pounds of this stuff, and cannot see any evidence of conchoidal fracturing on any of it. Nor can I see any conchoidal fractures after chipping/breaking pieces myself. Also, I collect a ton of various chalcedony material, & I know it's not an accurate or precise gauge, but the texture of the surface of this stuff just doesn't feel similar to the various agates, cherts and jasper's that I collect. So I have a little doubt, but do expect that it will be quartz of some kind.
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