Powellite
A variety of Scheelite Group
What is Powellite?
Powellite is an unusual, molybdenum-containing mineral that appears in a variety of colors, though it is most commonly whitish or yellowish. The mineral was discovered in Idaho in the 1890s and was named for John Wesley Powell, a famed geologist and explorer who spent much time delving into the mineralogy and geology of the American west. Powellite is not used industrially or commercially, though some exceptionally-colored specimens may be sought after by collectors.
Etymology & Origins
Powellite was first described by William Harlow Melville in 1891 for an occurrence in the Peacock Mine, Adams County, Idaho and named for American explorer and geologist, John Wesley Powell (1834–1902).
Optical Properties
- Refractive Index
- 1.974-1.984
- Pleochroism
- Deeply colored specimens - Blue, green
- Optical Character
- Biaxial positive
Market Value Factors
Pricing varies for every rock and mineral, so use these universal factors to gauge Powellite before comparing listings or appraisals.
Size & Weight
Larger, intact specimens usually command higher prices.
Rarity & Demand
Scarce material or popular varieties sell at a premium.
Condition & Finish
Chips, repairs, and heavy wear lower value; clean prep helps.
Treatment & Provenance
Untreated specimens with documented locality are prized.
Powellite Localities Map
See where Powellite is found with a localities map, collecting zones, and geology context. Generate a sample map preview below.
Health & Safety Information
- ⚠️Powellite dust is toxic because it contains heavy metals Molybdenum.
- ⚠️Molybdenum
- ⚠️Powellite is considered low risk for typical human exposure, but it can be toxic to some animals, such as cattle and sheep. It's important to store it out of the reach of animals.
Quick Facts
Physical Properties
- Color
- Yellow, straw-yellow, yellow-brown, brown, greenish yellow, grey, blue, black, colourless, black material is deep blue in transmitted light
- Hardness (Mohs)
- 3.5 - 4
- Density
- 4.255 g/cm³
- Streak
- Light yellow
- Luster
- Pearly, Resinous, Sub-adamantine
- Crystal System
- Tetragonal
Chemical Properties
- Chemical Formula
- Ca(MoO4)
- Elements
- Ca, Mo, O
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Powellite FAQs
How do I identify Powellite?
Powellite can be identified by its hardness of 3.5 - 4 on the Mohs scale, Yellow color, Pearly, Resinous, Sub-adamantine luster, Tetragonal crystal system. Look for these key characteristics when examining specimens.
What color is Powellite?
Powellite typically appears in Yellow, straw-yellow, yellow-brown, brown, greenish yellow, grey, blue, black, colourless, black material is deep blue in transmitted light. Color can vary depending on impurities and formation conditions.
How hard is Powellite?
Powellite has a hardness of 3.5 - 4 on the Mohs scale. This gives it moderate hardness.
