Yavapaiite is a rare potassium iron sulfate typically found as an oxidation product in mine dumps or as a fumarolic deposit. It usually occurs as small, delicate tabular crystals or thin crusts, often associated with other iron-bearing sulfates.
Is this yavapaiite?
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 yavapaiite with a known reference. Yavapaiite sits at Mohs 2.5-3, softer than the next harder reference, harder than the previous one.
- 2Check the streakDrag the specimen across an unglazed porcelain plate. Streak: white to pale yellow.
- 3Read the lusterHold the specimen under a strong light. Luster: vitreous to nearly adamantine.
- 4Match the color rangeCompare against the expected color range: light pink.
- 5Look at form & habitCrystal system: monoclinic. Typical habit: acicular, microscopic crystals.
Often confused with
Yavapaiite vs. its common look-alikes, and how to tell them apart in the field.
How to tell apart: Streak differs, so Yavapaiite leaves white to pale yellow, Jarosite leaves pale yellow; luster reads vitreous to nearly adamantine on Yavapaiite and subadamantine to vitreous, resinous on fractures on Jarosite.
How to tell apart: Yavapaiite is noticeably harder (Mohs 2.5-3 vs. 1.5); streak differs, so Yavapaiite leaves white to pale yellow, Millosevichite leaves red.
Often found alongside yavapaiite
Minerals reported to co-occur with yavapaiite. Spotting these in float or country rock is a strong cue you are in the right ground.
All properties
- Chemical formula
- KFe(SO₄)₂
- Mohs hardness
- 2.5-3
- Density
- 2.88 g/cm³
- Colors
- Streak
- White to pale yellow
- Luster
- Vitreous to nearly adamantine
- Transparency
- Transparent
- Crystal system
- Monoclinic
- Crystal habit
- Acicular, microscopic crystals
- Cleavage
- Perfect on {001}, {100}; distinct on {110}
- Rarity
- Rare
- Uses
- Collector
- Host rock
- In the fire zone of a pyritic orebody, formed under fumarolic conditions
Where rockhounds find yavapaiite
Classic worldwide localities
- United Verde Extension mine, Jerome, Arizona, USA (type locality)
Field-hunting tip
Where it forms: In the fire zone of a pyritic orebody, formed under fumarolic conditions. If you start seeing voltaite, sulfur, jarosite in float, you are in the right ground. Typical habit: acicular, microscopic crystals. Train your eye for that shape before scanning the outcrop.
Common questions
How do you identify yavapaiite?+
Where is yavapaiite found?+
What rocks look like yavapaiite?+
What minerals are found with yavapaiite?+
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What is yavapaiite used for?+
Find yavapaiite on the map
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