Gemstone Encyclopedia

Why Specific Gravity Helps Separate Clear Quartz from Glass

Why Specific Gravity Helps Separate Clear Quart...

Clear quartz has a specific gravity near 2.65, while common glass is often 2.4 to 2.5. Learn how density helps distinguish quartz from glass and why optical tests still matter.

Why Specific Gravity Helps Separate Clear Quart...

Clear quartz has a specific gravity near 2.65, while common glass is often 2.4 to 2.5. Learn how density helps distinguish quartz from glass and why optical tests still matter.

Why Mahogany Obsidian Specimens Look So Different: Iron Oxide, Flow Banding, and the Limits of a Single Color Explanation

Why Mahogany Obsidian Specimens Look So Differe...

Why mahogany obsidian specimens look different: natural glass formation, iron oxide particles, flow banding, vesicles, and the limits of a single chromophore explanation.

Why Mahogany Obsidian Specimens Look So Differe...

Why mahogany obsidian specimens look different: natural glass formation, iron oxide particles, flow banding, vesicles, and the limits of a single chromophore explanation.

What Aquamarine's Internal Growth Patterns Reveal About Its Formation

What Aquamarine's Internal Growth Patterns Reve...

Explore how aquamarine's internal growth structures form, what they reveal about pegmatitic and hydrothermal origins, and how they help identify natural, synthetic, and treated beryl.

What Aquamarine's Internal Growth Patterns Reve...

Explore how aquamarine's internal growth structures form, what they reveal about pegmatitic and hydrothermal origins, and how they help identify natural, synthetic, and treated beryl.

Why Specific Gravity Is a Useful but Limited Test for Vesuvianite

Why Specific Gravity Is a Useful but Limited Te...

Vesuvianite specific gravity is useful but not definitive. Learn its typical range, why it varies, and how it compares with green garnet, diopside, epidote, and peridot.

Why Specific Gravity Is a Useful but Limited Te...

Vesuvianite specific gravity is useful but not definitive. Learn its typical range, why it varies, and how it compares with green garnet, diopside, epidote, and peridot.

How Gemologists Tell Natural Green Sapphire from Synthetic Green Sapphire

How Gemologists Tell Natural Green Sapphire fro...

How gemologists distinguish natural green sapphire from synthetic corundum using growth structures, inclusions, trace elements, and spectroscopy.

How Gemologists Tell Natural Green Sapphire fro...

How gemologists distinguish natural green sapphire from synthetic corundum using growth structures, inclusions, trace elements, and spectroscopy.

Sinhalite and the Problem of Names That Outlive Their Evidence

Sinhalite and the Problem of Names That Outlive...

Sinhalite was first classified as an olivine variety but is now recognized as a distinct magnesium aluminum borate. Learn why the name stayed and what separates it from forsterite.

Sinhalite and the Problem of Names That Outlive...

Sinhalite was first classified as an olivine variety but is now recognized as a distinct magnesium aluminum borate. Learn why the name stayed and what separates it from forsterite.