The mineralogy behind the stone
Less shop-talk, more geology — what each crystal actually is, how it forms, and how to tell similar stones apart.
What Is Topaz? Almost All Blue Topaz Has Been Irradiated
Natural blue topaz is extremely rare and pale — nearly all vivid blue topaz on the market has been irradiated and heat-treated.
What Is Amazonite? A Name That's Actually a Historical Mistake
Amazonite's name suggests it comes from the Amazon — but no amazonite has ever actually been found in that region.
What Is Amber? It's Not a Mineral — It's Fossilized Tree Resin
Amber isn't a mineral at all — it's fossilized tree resin, and it can trap insects that lived millions of years ago.
What Is a Pearl? Not a Mineral or Crystal at All
A pearl isn't a mineral or crystal — it's formed inside a living mollusk, and "cultured" doesn't mean fake.
What Is Larimar? A Gemstone Found in Only One Place on Earth
Larimar is a genuine geographic rarity — gem-quality material has only ever been found in one specific region of the Dominican Republic.
What Is Chrysocolla? Often Confused With Turquoise, But a Different Mineral
Chrysocolla shares turquoise's blue-green color but is chemically distinct, and usually too soft for jewelry unless combined with quartz.
What Is Kunzite? A Stone That Changes Color With the Angle You View It
Kunzite shows different color intensity depending on the angle you view it from — and it can fade with prolonged light exposure.
What Is Iolite? The Stone Vikings May Have Used to Navigate
Iolite shows three different colors from three different angles — a property historically linked to Viking navigation on cloudy days.
What Is Zircon? The Oldest Mineral on Earth — and Nothing Like Cubic Zirconia
Zircon is a genuine natural gemstone, unrelated to synthetic cubic zirconia — and it's literally used to date the age of Earth's crust.
What Is Spinel? The Gem Mistaken for Ruby in the Crown Jewels
For centuries, some of history's most famous "rubies" — including one in the British Crown Jewels — turned out to be spinel.
What Is Kyanite? A Mineral With Different Hardness Depending on Direction
Kyanite has a genuinely unusual property: it's harder in one direction than another, within the exact same crystal.
What Is Prehnite? The First Mineral Ever Named After a Person
Prehnite holds a genuine mineralogical first — it was the first mineral ever named after a specific person.
What Is Jade? Two Different Minerals Share One Name
A full look at jade — the jadeite/nephrite distinction, how jadeite treatments are graded (Type A/B/C), and its cultural weight in China.
What Is Opal? Also Not Technically a Mineral
A full look at opal — the different types, how play-of-color actually works, and what a "doublet" or "triplet" opal really is.
What Is Pyrite? The Real Story Behind "Fool's Gold"
A full look at pyrite — how to tell it from real gold, its relationship to marcasite, and its surprising role before modern firearms.
What Is Agate? Most of Its Bright Color Is Dyed
A full look at agate — how its bands actually form, the moss agate exception, and why so much of its color is dyed.
What Is Sodalite? Often Mistaken for Lapis Lazuli
A full look at sodalite — its family connection to lapis lazuli's lazurite, the UV test that tells them apart, and where it's mined.
What Is Garnet? A Mineral Group, Not One Stone
A full look at garnet — the six main species within the group, the rare color-change variety, and its industrial uses.
What Is Peridot? A Gem That Forms Deep in the Earth's Mantle
A full look at peridot — why it forms in the mantle rather than the crust, its meteorite connection, and its historical sources.
What Is Sunstone? The Sparkle Is a Different Effect Than Moonstone's
A full look at sunstone — the reflective platelets behind its sparkle, and what makes Oregon's copper-bearing material unique.
What Is Malachite? A Banded Copper Mineral, With a Practical Note
A full look at malachite — how its bands form, its connection to azurite, and its long history as a pigment and decorative stone.
What Is Fluorite? The Mineral That Gave "Fluorescent" Its Name
A full look at fluorite — the cleavage mechanics behind its shape, its industrial role, and where the word "fluorescence" came from.
What Is Howlite? The Stone Often Sold as Turquoise
A full look at howlite — its actual mineral chemistry, why it takes dye so well, and how to spot it versus real turquoise.
What Is Lapis Lazuli? Actually a Rock, Not a Mineral
A full look at lapis lazuli — the rock behind the pigment ultramarine, how it's graded, and how to spot common imitations.
What Is Carnelian? The Chemistry Behind Its Orange-Red
A full look at carnelian — the iron chemistry behind its color, its ancient heat-treatment history, and how it differs from sard.
What Is Obsidian? Not a Mineral at All
A full look at obsidian — why it's volcanic glass rather than a mineral, its varieties, and its history as the sharpest edge humans ever made.
What Is Selenite? A Stone That Dissolves in Water
A full look at selenite — its gypsum chemistry, the desert rose formation, and the extraordinary crystals of Mexico's Naica cave.
What Is Amethyst? The Chemistry Behind Its Purple
An in-depth reference on amethyst — the chemistry behind its purple, grading, historical value, and answers to common questions.
What Is Clear Quartz? The Most Common Crystal on Earth
A full look at clear quartz — why it's the most abundant crystal on Earth, its piezoelectric property, and common inclusions.
What Is Labradorite? The Physics Behind Its Flash
A full look at labradorite — the interference physics behind its flash, grading by schiller strength, and where spectrolite comes from.
What Is Tourmaline? A Mineral Family, Not One Stone
A full look at tourmaline — why it comes in so many colors, its unusual electrical properties, and what makes Paraíba tourmaline so rare.
What Is Lemon Quartz? Why Its Color Isn't Natural
A full look at lemon quartz — how irradiation produces its color, and how to tell it apart from genuine citrine.
What Is Citrine — and Why Is Most of It Not Natural?
An in-depth reference on citrine — why natural citrine is rare, grading, its Art Deco history, and answers to common questions.
What Is Smoky Quartz? The Science Behind Its Color
A full look at smoky quartz — the radiation-driven color science behind it, natural vs. lab-irradiated material, and where it's mined.
What Is Turquoise? A Porous Stone That's Almost Always Treated
An in-depth reference on turquoise — chemistry, stabilization, grading by mine, 7,000 years of history, and answers to common questions.
What Is Moonstone? The Optics Behind Its Glow
A full look at moonstone — the optical physics behind adularescence, how it differs from labradorite, and where the finest material is found.
What Is Aquamarine? A Close Cousin of Emerald
A full look at aquamarine — its place in the emerald family, why nearly all of it is heat-treated, and how grading works.
What Is Rose Quartz?
An in-depth reference on rose quartz — formation, color science, grading, historical use, and answers to common questions.
Tiger's Eye vs. Hawk's Eye: What's the Difference?
A full look at tiger's eye and hawk's eye — the fibrous structure behind their chatoyancy, and exactly what separates the two.