Curtisite is a rare organic mineral typically found in mercury-rich hydrothermal deposits. It is best identified by its distinct yellowish-green color and intense fluorescence under ultraviolet light.
Is this curtisite?
5-step field checkRun through these checks against the specimen in your hand. The more boxes tick, the more confident the ID.
- 1Test the hardnessTry to scratch curtisite with a known reference. Curtisite sits at Mohs 1-2 — softer than the next harder reference, harder than the previous one.
- 2Check the streakDrag the specimen across an unglazed porcelain plate. Curtisite leaves a yellow streak.
- 3Read the lusterHold the specimen under a strong light. Curtisite typically shows a resinous luster.
- 4Match the color rangeCompare against the expected color range: yellow, yellowish-green, brownish-yellow.
- 5Look at form & habitCrystal system: orthorhombic. Typical habit: platy crystals, granular, massive.
Often confused with
Curtisite vs. its common look-alikes — and how to tell them apart in the field.
Often found alongside curtisite
Minerals reported to co-occur with curtisite. Spotting these in float or country rock is a strong cue you are in the right ground.
All properties
- Chemical formula
- C₂₄H₁₈
- Mohs hardness
- 1-2
- Density
- 1.24 g/cm³
- Streak
- Yellow
- Luster
- Resinous
- Transparency
- Translucent
- Crystal system
- Orthorhombic
- Crystal habit
- Platy Crystals, Granular, Massive
- Cleavage
- None
- Fluorescence
- Bright Yellow-green Under UV
- Rarity
- Rare
- Uses
- Collector
- Host rock
- Mercury-bearing Hydrothermal Deposits
- Typical price
- $20-150 for small specimens
Where rockhounds find curtisite
1 mapped spotsClassic worldwide localities
- California, USA
- Idria, Slovenia
- Texas, USA
Field-hunting tip
Look in mercury-bearing hydrothermal deposits country — that is the host setting where curtisite typically forms. If you start seeing cinnabar, quartz, calcite in float, you are in the right ground. Field specimens usually show a platy crystals, granular, massive habit, so train your eye for that shape before scanning the outcrop. In the U.S., the densest reported localities are in California — start trip planning there.
Common questions
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Find curtisite on the map
RockHoundR shows mapped rockhounding spots, access rules, and lets you log every find.
