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Gemstone Encyclopedia
Azurite’s Shifting Surfaces: Why Some Blue Spec...
Azurite’s blue is a copper-absorption body color, while its iridescent sheen is surface interference. Learn why the effect varies between specimens and how gemologists distinguish it.
Azurite’s Shifting Surfaces: Why Some Blue Spec...
Azurite’s blue is a copper-absorption body color, while its iridescent sheen is surface interference. Learn why the effect varies between specimens and how gemologists distinguish it.
Green Sapphire and Its Host Rocks: Reading Trea...
How metamorphic and placer host rocks shape green sapphire's natural zoning, inclusions, and how gemologists reason about heating, diffusion, and filling without confusing geology with proof.
Green Sapphire and Its Host Rocks: Reading Trea...
How metamorphic and placer host rocks shape green sapphire's natural zoning, inclusions, and how gemologists reason about heating, diffusion, and filling without confusing geology with proof.
Oligoclase Feldspar: Reading a Solid Solution i...
Oligoclase is a plagioclase feldspar with a variable composition. Learn how solid solution affects its refractive index, specific gravity, and trade descriptions, and why precise species identification requires laboratory analysis.
Oligoclase Feldspar: Reading a Solid Solution i...
Oligoclase is a plagioclase feldspar with a variable composition. Learn how solid solution affects its refractive index, specific gravity, and trade descriptions, and why precise species identification requires laboratory analysis.
Why Blue Lace Agate Looks Soft: Porosity, Hydra...
Why blue lace agate looks soft despite quartz hardness: its cryptocrystalline structure, porosity, water content, light scattering, banded formation, and identification limits explained.
Why Blue Lace Agate Looks Soft: Porosity, Hydra...
Why blue lace agate looks soft despite quartz hardness: its cryptocrystalline structure, porosity, water content, light scattering, banded formation, and identification limits explained.
Red Aventurine as a Composite Material: Why One...
Red aventurine is not a mineral species but a trade name for a heterogeneous quartz rock and for manufactured glass. Learn why its properties vary and how the materials differ.
Red Aventurine as a Composite Material: Why One...
Red aventurine is not a mineral species but a trade name for a heterogeneous quartz rock and for manufactured glass. Learn why its properties vary and how the materials differ.
Satin Spar and the Problem of a Name That Descr...
Satin spar is a fibrous habit name, not a mineral species. Learn how gypsum, calcite, and aragonite relate to the term and why the silky label complicates gemological identification.
Satin Spar and the Problem of a Name That Descr...
Satin spar is a fibrous habit name, not a mineral species. Learn how gypsum, calcite, and aragonite relate to the term and why the silky label complicates gemological identification.