pearly lustre

mineralogy

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July 1, 2026

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In mineralogy, lustre describes the way a mineral's surface reflects light. Pearly lustre is a type of nonmetallic lustre that resembles the sheen of pearl or mother-of-pearl. This appearance is often seen on mineral surfaces parallel to well-developed cleavage planes, resulting from repeated reflections from tiny cracks within the mineral. Talc is an example of a mineral that can exhibit a pearly lustre. Lustre depends on a mineral's refractive power, transparency, and structure.12

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mineral
Lustre
…is common in sphalerite [ZnS]); pearly, having the lustre of mother-of-pearl (i.e., an iridescent pearl-like lustre characteristic of mineral surfaces that are parallel to well-developed cleavage planes; the cleavage surface of talc [Mg₃Si₄O₁₀(OH)₂] may show pearly lustre); greasy, having the appearance of being covered with a thin layer of oil…
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…is common in sphalerite [ZnS]); pearly, having the lustre of mother-of-pearl (i.e., an iridescent pearl-like lustre characteristic of mineral surfaces that are parallel to well-developed cleavage planes; the cleavage surface of talc [Mg₃Si₄O₁₀(OH)₂] may show pearly lustre); greasy, having the appearance of being covered with a thin layer of oil…
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