Wurtzite is a hexagonal polymorph of zinc sulfide, often found in low-temperature hydrothermal veins. It typically displays brownish, resinous pyramidal crystals or fibrous crusts that can be easily mistaken for its common cousin, sphalerite.
Is this wurtzite?
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 wurtzite with a known reference. Wurtzite sits at Mohs 3.5-4, softer than the next harder reference, harder than the previous one.
- 2Check the streakDrag the specimen across an unglazed porcelain plate. Wurtzite leaves a brownish-yellow to light brown streak.
- 3Read the lusterHold the specimen under a strong light. Wurtzite typically shows a resinous luster.
- 4Match the color rangeCompare against the expected color range: brown, yellowish-brown, reddish-brown, black.
- 5Look at form & habitCrystal system: hexagonal. Typical habit: pyramidal crystals, fibrous, massive, or crusts.
Often confused with
Wurtzite vs. its common look-alikes, and how to tell them apart in the field.
How to tell apart: Streak differs, so Wurtzite leaves brownish-yellow to light brown, Sphalerite leaves white to yellow-brown; luster reads resinous on Wurtzite and resinous to submetallic on Sphalerite.
How to tell apart: Streak differs, so Wurtzite leaves brownish-yellow to light brown, Greenockite leaves brick-red to orange-yellow; luster reads resinous on Wurtzite and adamantine to resinous on Greenockite.
Often found alongside wurtzite
Minerals reported to co-occur with wurtzite. Spotting these in float or country rock is a strong cue you are in the right ground.
All properties
- Chemical formula
- ZnS
- Mohs hardness
- 3.5-4
- Density
- 3.98-4.08 g/cm³
- Streak
- Brownish-yellow to Light Brown
- Luster
- Resinous
- Transparency
- Translucent
- Crystal system
- Hexagonal
- Crystal habit
- Pyramidal Crystals, Fibrous, Massive, Or Crusts
- Cleavage
- Distinct On {1120}
- Rarity
- Uncommon
- Uses
- Collector, Scientific Research
- Host rock
- Hydrothermal Veins, Low-temperature Ore Deposits
- Typical price
- $10-100 for thumbnail to small cabinet specimens
Where rockhounds find wurtzite
1 mapped spotsClassic worldwide localities
- Príbram, Czech Republic
- Oruro, Bolivia
- Bingham, New Mexico, USA
- Tsumeb, Namibia
Field-hunting tip
Look in hydrothermal veins, low-temperature ore deposits country, the host setting where wurtzite typically forms. If you start seeing sphalerite, galena, pyrite in float, you are in the right ground. Field specimens usually show a pyramidal crystals, fibrous, massive, or crusts habit, so train your eye for that shape before scanning the outcrop. In the U.S., the densest reported localities are in Pennsylvania. Start trip planning there.
Common questions
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Find wurtzite on the map
RockHoundR shows mapped rockhounding spots, access rules, and lets you log every find.
