Sulfur

A native element that crystallizes around volcanic vents and in salt domes. Unmistakably bright yellow.

Sulfur specimen — Photo: Ivar Leidus, CC BY-SA 4.0, via Wikimedia Commons

How to identify sulfur

Bright lemon yellow.
Very light and soft.
Smells like rotten matches when warmed or rubbed.
Melts and burns with a blue flame.

Often confused with

Calcite
Yellow calcite is harder, fizzes in acid and has no smell.
Compare side by side

Where it's found

Kawah Ijen, Indonesia
Agrigento, Sicily
Gulf Coast salt domes, USA
Bolivia

Uses

Sulfuric acid (the most-produced industrial chemical), fertilizer and vulcanized rubber.

Rock tumbling

Not suitable for tumbling.

Did you know?

Hold a sulfur crystal in a warm hand and it may crackle — the heat makes it expand and fracture.

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