Goethite in Quartz

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Geopressure
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Goethite in Quartz

Post by Geopressure »

It's been a while since my last post..here is a spray of Goethite (tentative ID) with Quartz. They grew inside an agate geode from Argentina. Nothing like trying to illuminate something in a cavity. Under the scope these Goethite crystals tend to either look like silver mirrors or black, so this image is sort of a compromise. They do have some color but the luster obscures it. Next I'll probably try cross polarization.

Stacked at 5X
F.O.V. 3.7mm


Image
Brad

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Saul
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Post by Saul »

Impressive structures.
Saul
μ-stuff

physicsmajor
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Post by physicsmajor »

This is fantastic! I like how you can tell the quartz was the 2nd generation growing around one of the crystals on the right. Is this in one of the red amethyst geodes which hit the market about 2 years back?

I'll have to go back and check your prior posts to see more - mineral work is one of my primary interests. Was this under a true scope, or a 5x lens/objective mounted to a DSLR?

Geopressure
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Post by Geopressure »

Glad you liked it, PhysicsMajor. This is actually from a small agate nodule. When I sawed it open it happened to have a hollow center with the Goethite as a bonus. You are correct that this was shot using a 5X microscope objective with a tube lens mounted on a DSLR. It's always good to meet another mineral lover.
Brad

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Harald
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Post by Harald »

Hi Geopressure,
Love micro minerals...

They are fascinating and a joy to photograph.
Light is the big challenge with all the reflections.

Going to do some next week I think.

Keep those images coming and thanks for sharing :D
Kind Regards
Harald

Lier Fotoklubb / NSFF
AFIAP / CPS
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physicsmajor
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Post by physicsmajor »

I'd like to follow up on the lighting - this is a very nice balance between getting mild reflections from the facets at the tips, while allowing the black to show deeper which gives us the correct perception that these crystals are black and quite reflective.

How did you go about lighting this?

Geopressure
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Post by Geopressure »

Physicsmajor: As to the lighting..I was fortunate in that the crystals are somewhat parallel. This allowed me to use a diffused, but still rather directional LED light source oriented to minimize any specular reflections. This did create some shadows but it worked out OK. Nice uniform lighting tended to leave all the faces looking like mirrors. Hope that helps.
Brad

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RoxnDox
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Post by RoxnDox »

That is just flat-out gorgeous...
I go by "Jim" in real life, "RoxnDox" on here...

Geopressure
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Post by Geopressure »

Thanks RoxnDox..glad you approve!
Brad

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