90 degree corners on growth lines?

[Lee Little]

This stone was sold as Amethyst, matches Amethyst on RI but has what appears to be 90 degree corners on growth lines? Anybody have a clue how this is possible? Best regards, Lee

 

[Michael_E]

It could be a phantom, where the iron causing the purple coloration varied in concentration in the hydrothermal fluids, from low to high and back again as the crystal tip was growing.

 

[Lee Little]

I believe you hit the nail on the head Micheal, some other friends said the same thing.
In case some don't know what a phantom is, it is when a crystal grows over an older crystal and the older one becomes a phantom crystal shape inside the new crystal. There are some crystals that have several phantoms inside and I always thought they looked cool, I just never knew what they looked like once they were faceted. My brain about blew a fuse when I noticed them, LOL. I would imagine that many are never faceted since they are a collectors specimen as is so they already have a value. Best regards, Lee

 

[Richard M.]

Is the area I've circled, where the two sets of colored growth lines intersect at 90 degrees, what you're talking about Lee?

If so I don't see how phantom growth could cause it.

Richard M. (Rick Martin)

 

[Lee Little]

Hi Rick,
The area you circled is where the 90 degree corners are, however, they do not appear to intersect. Best regards, Lee