Evansite is a rare hydrous aluminum phosphate mineral often found as botryoidal or stalactitic crusts. It is easily confused with opal due to its amorphous, glassy appearance, but it is typically identified by its distinctive bright green fluorescence under UV light.
Is this evansite?
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 evansite with a known reference. Evansite sits at Mohs 3-4, softer than the next harder reference, harder than the previous one.
- 2Check the streakDrag the specimen across an unglazed porcelain plate. Streak: white or slightly tinted.
- 3Read the lusterHold the specimen under a strong light. Luster: vitreous to resinous or waxy.
- 4Match the color rangeCompare against the expected color range: colorless, white, yellow, green, blue.
- 5Look at form & habitCrystal system: amorphous. Typical habit: botryoidal, reniform, stalactitic.
Often confused with
Evansite vs. its common look-alikes, and how to tell them apart in the field.
Often found alongside evansite
Minerals reported to co-occur with evansite. Spotting these in float or country rock is a strong cue you are in the right ground.
All properties
- Chemical formula
- Al₃PO₄(OH)₆·8H₂O
- Mohs hardness
- 3-4
- Density
- 2.0 g/cm³
- Streak
- White or slightly tinted
- Luster
- Vitreous to resinous or waxy
- Transparency
- Transparent to translucent
- Crystal system
- Amorphous
- Crystal habit
- Botryoidal, reniform, stalactitic
- Cleavage
- None
- Rarity
- Uncommon
- Uses
- Collector, Scientific research
- Host rock
- In a graphite deposit (Gross-Tresny, Czech Republic); in graphitic gneiss (Vatoinandry district, Madagascar); in coal seams (Alabama, USA); a coating in caves, the phosphate derived from guano
Where rockhounds find evansite
Classic worldwide localities
- Columbiana and Coalville, Shelby Co., Alabama, USA
- Wilson Springs (Potash Sulphur Springs) mine, Garland Co., Arkansas, USA
- Goldburg, Custer Co., Idaho, USA
- Železník (Vashegy), Slovakia
- Nižná-Slaná, Czech Republic
- Alsô-Sajô, Romania
Field-hunting tip
Where it forms: In a graphite deposit (Gross-Tresny, Czech Republic); in graphitic gneiss (Vatoinandry district, Madagascar); in coal seams (Alabama, USA); a coating in caves, the phosphate derived from guano. If you start seeing variscite, allophane, limonite in float, you are in the right ground. Typical habit: botryoidal, reniform, stalactitic. Train your eye for that shape before scanning the outcrop.
Common questions
How do you identify evansite?+
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What rocks look like evansite?+
What minerals are found with evansite?+
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Find evansite on the map
RockHoundR shows mapped rockhounding spots, access rules, and lets you log every find.
