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Geology, 
explained.

Clear essays and videos on how the Earth actually works.

FOLDFAULTDYKEUNCONFORMITY01 — DEPOSITION02 — FOLDING03 — FAULTING04 — INTRUSION05 — EROSION06 — NEW DEPOSITIONTODAYREAD THE EARTH

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Hello! I make Geoscopy: videos and long-form essays about how the Earth actually works. The geology I grew up reading was either locked in textbooks nobody outside the field opens, or chopped into 30-second clips that miss the point. Geoscopy is what I wanted instead: the real science, explained clearly, without oversimplifications.

There’s 4.5 billion years of history under your feet. I’d like to teach you to read it.

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Specimen of the weekMineral · Phosphates

Apatite

Apatite is not just one neat mineral with one fixed composition. In everyday mineral collecting and geology, “apatite” is often used for a group of related calcium phosphate minerals.

Mohs hardness
5. Apatite is the reference mineral for hardness 5 on the Mohs scale.
Common simplified formula
Ca5(PO4)3(F, Cl, OH). The main end-members are fluorapatite, hydroxylapatite, and…
Crystal system
Hexagonal for the common apatite-group minerals.

Open the specimen

Orange and gray crystal mineral cluster specimen (monazite mineral)

Monazite

Green fluorite crystal on yellow mineral matrix

Fluorite

Black and white speckled diorite rock specimen

Diorite

White crystalline mineral rock specimen (marble specimen)

Marble

Translucent brown and amber feldspar crystals (feldspar specimen)

Feldspar

Cluster of shiny brown layered mica crystals on black background

Mica

Fossilized fish fin embedded in a gray rock slab (limestone)

Limestone

Pink mineral crystal resting on a green stone prism (apatite)

Apatite

Dark green pyroxene crystal cluster on matrix

Pyroxene

Dark red zircon crystal on pale mineral matrix

Zircon

Cluster of white calcite crystals (calcite specimen)

Calcite

Dark cubic mineral crystal on glittering rock matrix (Galena)

Galena

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