Faking Asterism - GIA

[SwordfishMining]

This topic came up in another thread on another platform and I figured it was worth sharing here too. You can fake that with a sanding job. A triplet gives it more surfaces to work with. "Although no one has come forward to say exactly how this process is being done, the appearance of the stones suggests that it involves the use of a polishing wheel with a coarse grit. The oriented scratches are numerous and packed tightly together, so some type of spinning wheel is probably involved. Also, the symmetry of most of the specimens would suggest that the process is being done by hand, rather than by some form of automation."

The GIA has seen some simulated asterism stones coming thru to be graded.
Its a PDF with pictures

CONCLUSION:
These imitation stars are not difficult to detect in most cases because of their unnatural appearance.
The key, as is often the case in gemology, is in knowing that such a treatment exists, understanding the sources and appearances of naturally occurring
phenomena such as asterism, and questioning any stone that appears suspicious. Microscopic examination should easily permit the identification, especially with the assistance of a fiber-optic light source. The presence of a natural 12-rayed star sapphire in one of the groups of suspect stones we received serves as a reminder that while stones with such a large number of rays are rare, they do exist. Only with careful microscopic examination can you conclusively prove the origin of the asterism. Even if a stone appears suspicious, you should follow through with the proper examination before pronouncing judgment.




https://www.gia.edu/doc/A-New-Method-fo ... terism.pdf

[OpalSpectrum]

kudos to cutters LOL