pearly luster; iridescence
Geological term describing a pearl-like sheen or play of colors, as seen in minerals such as nacre or opal.
This mineral has a pearly luster.
Pearly luster is the characteristic sheen seen in nacre.
光沢 is a general term for luster or gloss, while 真珠光沢 specifically refers to the pearly, iridescent luster found in pearls and some minerals.
Compound of 真珠 (pearl) and 光沢 (luster). The exact historical derivation is uncertain, but the term transparently describes a pearl-like sheen.