Asterism

A star of four, six or twelve rays across a cabochon, from oriented needle inclusions (rutile in star sapphire and ruby, in star garnet and diopside).

Sources

Gemological Institute of America — Gem encyclopedia and glossary
Mindat — Mineralogical glossary (link only)

Cite this article

Stratum Study. "Asterism" (Glossary). Stratum Study pack 2026.09, as of 2026-09-16. https://stratum.black/study/glossary/asterism. Accessed 2026-09-20.

BibTeX · CSL-JSON

@misc{stratum-asterism,
  title        = {Asterism},
  author       = {{Stratum Study}},
  howpublished = {\url{https://stratum.black/study/glossary/asterism}},
  year         = {2026},
  note         = {Glossary article, Stratum Study pack 2026.09, as of 2026-09-16; sources: stratum. Accessed 2026-09-20.}
}

Citations carry the pack version and the article's as-of date so they resolve to the same text later. The facts themselves belong to the sources listed below; cite those for the science.