Vanadinite Crystals
Moderators: rjlittlefield, ChrisR, Chris S., Pau
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Vanadinite Crystals
Vanadinite Crystals
A rock shop purchase put me in possession of some minute vanadinite crystals although larger ones can be had. I had always thought of crystal growth as following an orderly, uniform process. These very tiny crystals seem to have grown in total chaos.
I also assumed that the face surfaces would be smooth and inviolate to further growth. I was wrong on both counts. Stacked images
Walt
All images 6x on camera sensor. 4x objective.
Canon 50D on Leitz Ortholux microscope.
Zerene and Photoshop processing.
- rjlittlefield
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Lovely images!
Each of the crystals probably started from a single seed, with the seeds in random orientations. Growing outward from each seed, the crystal structure will be very orderly, until it happens to run into a crystal that is oriented differently because it is growing from a different seed. Then you get these beautiful intersecting structures.
In the few cases where we see small crystals sitting on the face of a large crystal, I would normally interpret those as due to small seeds that happened to fall onto the surface after the large crystal was well underway.
That explanation works very well for the first image, where the large and small crystals appear to have random orientations.
It does not work so well for the second image, right side, where all of the small crystals appear to have the same orientation as the large crystal. I do not have a comfortable explanation for what's happening there.
Spontaneous growth from the face does not seem likely, especially given the many other pristine faces. But it also does not seem likely that several new seeds would fall randomly in just the right orientation to produce the alignment that we see in the image. A fine mystery!
--Rik
Each of the crystals probably started from a single seed, with the seeds in random orientations. Growing outward from each seed, the crystal structure will be very orderly, until it happens to run into a crystal that is oriented differently because it is growing from a different seed. Then you get these beautiful intersecting structures.
In the few cases where we see small crystals sitting on the face of a large crystal, I would normally interpret those as due to small seeds that happened to fall onto the surface after the large crystal was well underway.
That explanation works very well for the first image, where the large and small crystals appear to have random orientations.
It does not work so well for the second image, right side, where all of the small crystals appear to have the same orientation as the large crystal. I do not have a comfortable explanation for what's happening there.
Spontaneous growth from the face does not seem likely, especially given the many other pristine faces. But it also does not seem likely that several new seeds would fall randomly in just the right orientation to produce the alignment that we see in the image. A fine mystery!
--Rik
I don't have comfortable explanations either, but small forces promote stacking faults in the lattice which then favour growth on different facets. Small changes in source element concentrations or temperature, likewise.
This is a crystal of the same stuff. Presumably there was less energy-based favouritism for particular growth facets here:
https://4.bp.blogspot.com/-aOEe_FsEpUc/ ... 1%2529.jpg
This is a crystal of the same stuff. Presumably there was less energy-based favouritism for particular growth facets here:
https://4.bp.blogspot.com/-aOEe_FsEpUc/ ... 1%2529.jpg
Chris R
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Gentlemen, thank you all for your comments.
Hi Rik. Thanks for the detailed look. You have a keen eye. I had not noticed the similar orientation of the small face crystals on the lower right image. Chris. I looked at your linked image. It’s interesting that they consider this vanadinite. It is so different from the shape of the crystals that I imaged. I love the translucence the photographer captured. I am hoping to capture something like that in the future.
Walt
Hi Rik. Thanks for the detailed look. You have a keen eye. I had not noticed the similar orientation of the small face crystals on the lower right image. Chris. I looked at your linked image. It’s interesting that they consider this vanadinite. It is so different from the shape of the crystals that I imaged. I love the translucence the photographer captured. I am hoping to capture something like that in the future.
Walt
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