Analysis of a transparent yellow angular crystal inclusion in a Brazilian rock crystal quartz host suggests monazite.

Nacreous pearls are known to have platelet growth resembling fingerprints or topographic maps, but a less common appearance is nacre with a concentric spiral pattern.

Remarkable “horsetail” inclusions discovered in a demantoid garnet, while their origin and composition remain under discussion.

One of the more subtle inclusion scenes gemologists sometimes observe in natural diamonds is the presence of crystallographically oriented structural defects known as “internal graining.”