Powellite is a molybdenum-bearing member of the scheelite group, most easily recognized by its vibrant yellow fluorescence under short-wave ultraviolet light. Collectors look for its characteristic tetragonal bipyramidal crystals, which are typically found as pseudomorphs after molybdenite or as vug linings in basaltic rocks.
Is this powellite?
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 powellite with a known reference. Powellite sits at Mohs 3.5, softer than the next harder reference, harder than the previous one.
- 2Check the streakDrag the specimen across an unglazed porcelain plate. Powellite leaves a white streak.
- 3Read the lusterHold the specimen under a strong light. Powellite typically shows a adamantine luster.
- 4Match the color rangeCompare against the expected color range: yellow, brown, greenish-yellow, white, gray.
- 5Look at form & habitCrystal system: tetragonal. Typical habit: bipyramidal crystals, granular, massive.
Often confused with
Powellite vs. its common look-alikes, and how to tell them apart in the field.
Often found alongside powellite
Minerals reported to co-occur with powellite. Spotting these in float or country rock is a strong cue you are in the right ground.
All properties
- Chemical formula
- CaMoO₄
- Mohs hardness
- 3.5
- Density
- 4.2-4.5 g/cm³
- Streak
- White
- Luster
- Adamantine
- Transparency
- Translucent
- Crystal system
- Tetragonal
- Crystal habit
- Bipyramidal Crystals, Granular, Massive
- Cleavage
- Distinct On {101}
- Fluorescence
- Bright Yellow Under SW UV
- Rarity
- Uncommon
- Uses
- Collector, Indicator Mineral
- Host rock
- Oxidized Zones of Molybdenum-bearing Hydrothermal Deposits and Basalt Cavities
- Typical price
- $20-150 thumbnail, $200-800 cabinet
Where rockhounds find powellite
Classic worldwide localities
- Needles, California, USA
- Krushev Dol, Bulgaria
- Moctezuma, Sonora, Mexico
- Maharashtra, India
Field-hunting tip
Look in oxidized zones of molybdenum-bearing hydrothermal deposits and basalt cavities country, the host setting where powellite typically forms. If you start seeing molybdenite, calcite, apophyllite in float, you are in the right ground. Field specimens usually show a bipyramidal crystals, granular, massive habit, so train your eye for that shape before scanning the outcrop.
Common questions
How do you identify powellite?+
Where is powellite found?+
How much is powellite worth?+
What rocks look like powellite?+
What minerals are found with powellite?+
What kind of rock does powellite form in?+
What is powellite used for?+
Find powellite on the map
RockHoundR shows mapped rockhounding spots, access rules, and lets you log every find.
