Given some crystal samples

[oneofone25]

This one has me stumped as it didn’t have a name on what it was.









I zoomed in around that black area with my OM 90mm f3.5 macro lens and MC-20 teleconverter. 4:1 magnification plus high resolution mode. Stack of maybe 20 images at 50mp each. Sharpened a tiny amount in Topaz.

Then I saved the file after editing in lightroom at 5,000 pixels on the long side. 4.35mm approximately field of vieW






here’s a crop showing that interesting area:







and further









what do you think?! Used OM Capture to move focus and hit shutter while in high resolution mode so I could manually bracket those high res images

 

[macrouser]

The shape of the crystals is a clue but I don't know enough to help. I hope someone knows enough.

 

[Ed Constable]

First guess, either galena or magnetite. As it seems to be in a geode, I would suggest (70%?), magnetite.