Gemstone Encyclopedia

Matrix Opal and the Misconception of a Mineral Identity

Matrix Opal and the Misconception of a Mineral ...

Matrix opal is a trade term for precious opal intergrown with host rock, not a single mineral variety. Learn why its identity as a composite affects identification and properties.

Matrix Opal and the Misconception of a Mineral ...

Matrix opal is a trade term for precious opal intergrown with host rock, not a single mineral variety. Learn why its identity as a composite affects identification and properties.

Why Does Vesuvianite Look Different Under Different Lights?

Why Does Vesuvianite Look Different Under Diffe...

Vesuvianite appears to change color under different lights, but this is caused by pleochroism, color zoning, and light-source spectrum rather than alexandrite-type color change.

Why Does Vesuvianite Look Different Under Diffe...

Vesuvianite appears to change color under different lights, but this is caused by pleochroism, color zoning, and light-source spectrum rather than alexandrite-type color change.

Emerald Formation and Deposit Type: Why Primary and Secondary Occurrences Matter

Emerald Formation and Deposit Type: Why Primary...

Learn how primary and secondary emerald deposits differ, why deposit type affects inclusions and gemological interpretation, and why origin cannot be determined from appearance alone.

Emerald Formation and Deposit Type: Why Primary...

Learn how primary and secondary emerald deposits differ, why deposit type affects inclusions and gemological interpretation, and why origin cannot be determined from appearance alone.

When Labradorite Flashes but Does Not Chatoy: Phenomena, Orientation, and the Limits of Trade Language

When Labradorite Flashes but Does Not Chatoy: P...

Why labradorite flashes without a cat's-eye band: labradorescence explained as thin-film interference from internal lamellae, and distinguished from chatoyancy, asterism, and adularescence.

When Labradorite Flashes but Does Not Chatoy: P...

Why labradorite flashes without a cat's-eye band: labradorescence explained as thin-film interference from internal lamellae, and distinguished from chatoyancy, asterism, and adularescence.

Phenakite and Its Mineral Associates: Reading a Rare Beryllium Silicate Through Its Host Rocks

Phenakite and Its Mineral Associates: Reading a...

Phenakite is a beryllium silicate mineral found in pegmatites and metamorphic rocks. Learn how its host-rock relationships, optical properties, and rarity as a gemstone distinguish it from quartz, beryl, and...

Phenakite and Its Mineral Associates: Reading a...

Phenakite is a beryllium silicate mineral found in pegmatites and metamorphic rocks. Learn how its host-rock relationships, optical properties, and rarity as a gemstone distinguish it from quartz, beryl, and...

Distinguishing Lepidolite from Pink Tourmaline, Rose Quartz, and Other Lookalikes

Distinguishing Lepidolite from Pink Tourmaline,...

Learn how lepidolite differs from pink tourmaline and rose quartz through cleavage, hardness, specific gravity, and optical properties, and how laboratory-grown lithium mica is produced.

Distinguishing Lepidolite from Pink Tourmaline,...

Learn how lepidolite differs from pink tourmaline and rose quartz through cleavage, hardness, specific gravity, and optical properties, and how laboratory-grown lithium mica is produced.