I have been playing again. This crystal turned out quite well, I believe.
Do we have any rockhounds in the forum, who would like to have a guess about what family/species it is?
Lens: semi-antique Zuiko 50mm macro. Developed in darktable & framed in The Gimp/g’mic.
I am impressed by your suggestions; more or less all of them present some grain of truth - even if I cannot vouch for Mica’s elusive carrot crystal, since it does not seem to thrive this far North.
The proper scientific name of my “crystal” is Citrus sinensis, and here is the same shot developed in a more conventional way: