Gemstone Encyclopedia

When Scapolite Is Not Scapolite: Clarity, Trade Names, and the Lookalikes That Mislead

When Scapolite Is Not Scapolite: Clarity, Trade...

Scapolite is a mineral series whose transparency varies widely. Learn why clean scapolite resembles amethyst and other gems, and how gemologists separate them.

When Scapolite Is Not Scapolite: Clarity, Trade...

Scapolite is a mineral series whose transparency varies widely. Learn why clean scapolite resembles amethyst and other gems, and how gemologists separate them.

Refractive Index, Birefringence, and the Optical Character of Blue Lace Agate: Why This Banded Chalcedony Behave So Differently from Transparent Quartz

Refractive Index, Birefringence, and the Optica...

Why blue lace agate behaves optically unlike transparent quartz: refractive index, birefringence, optical character, and the role of cryptocrystalline aggregate structure.

Refractive Index, Birefringence, and the Optica...

Why blue lace agate behaves optically unlike transparent quartz: refractive index, birefringence, optical character, and the role of cryptocrystalline aggregate structure.

Is Tanzanite's Color Change Real? Pleochroism, Lighting, and What the Eye Actually Sees

Is Tanzanite's Color Change Real? Pleochroism, ...

Tanzanite's blue-to-violet variation is direction-dependent pleochroism influenced by lighting, not true color change like alexandrite. Learn the optical mechanism, the role of vanadium, cutting orientation, and identification limits.

Is Tanzanite's Color Change Real? Pleochroism, ...

Tanzanite's blue-to-violet variation is direction-dependent pleochroism influenced by lighting, not true color change like alexandrite. Learn the optical mechanism, the role of vanadium, cutting orientation, and identification limits.

Why Nephrite Forms Where It Does: Metamorphic Conditions, Fluid Chemistry, and the Limits of Serpentinite Replacement

Why Nephrite Forms Where It Does: Metamorphic C...

Nephrite formation depends on bulk chemistry, fluid composition, metamorphic grade, and deformation. This article explains why nephrite is a rock, not a mineral, and why it forms only in narrow...

Why Nephrite Forms Where It Does: Metamorphic C...

Nephrite formation depends on bulk chemistry, fluid composition, metamorphic grade, and deformation. This article explains why nephrite is a rock, not a mineral, and why it forms only in narrow...

Pyrope Garnet and the Limits of Synthetic Equivalents

Pyrope Garnet and the Limits of Synthetic Equiv...

Why synthetic pyrope is uncommon, how synthetic garnet-structure materials differ from natural pyrope, and how to distinguish phenomenal garnet specimens from lookalikes.

Pyrope Garnet and the Limits of Synthetic Equiv...

Why synthetic pyrope is uncommon, how synthetic garnet-structure materials differ from natural pyrope, and how to distinguish phenomenal garnet specimens from lookalikes.

Amber Fluorescence: Why UV Light Reveals Uneven Color in Fossil Resin

Amber Fluorescence: Why UV Light Reveals Uneven...

Amber fluorescence is often uneven because fossil resin varies chemically and oxidizes unevenly. Learn what causes patchy UV glow and how to interpret it gemologically.

Amber Fluorescence: Why UV Light Reveals Uneven...

Amber fluorescence is often uneven because fossil resin varies chemically and oxidizes unevenly. Learn what causes patchy UV glow and how to interpret it gemologically.