Lópezite is an extremely rare, water-soluble potassium dichromate mineral found almost exclusively in the nitrate deposits of the Atacama Desert. It is highly valued by mineral collectors for its distinct, vibrant orange-red color and glass-like luster, but it must be stored in a dry, airtight environment due to its solubility and susceptibility to environmental humidity.
Is this lópezite?
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 lópezite with a known reference. Lópezite sits at Mohs 2.5, softer than the next harder reference, harder than the previous one.
- 2Check the streakDrag the specimen across an unglazed porcelain plate. Lópezite leaves a yellowish-orange streak.
- 3Read the lusterHold the specimen under a strong light. Lópezite typically shows a vitreous luster.
- 4Match the color rangeCompare against the expected color range: orange, red-orange.
- 5Look at form & habitCrystal system: triclinic. Typical habit: tabular crystals, crusts, or granular.
Often confused with
Lópezite vs. its common look-alikes, and how to tell them apart in the field.
How to tell apart: Streak differs, so Lópezite leaves yellowish-orange, Crocoite leaves orange-yellow; luster reads vitreous on Lópezite and adamantine on Crocoite.
How to tell apart: Streak differs, so Lópezite leaves yellowish-orange, Wulfenite leaves white; luster reads vitreous on Lópezite and resinous on Wulfenite.
Often found alongside lópezite
Minerals reported to co-occur with lópezite. Spotting these in float or country rock is a strong cue you are in the right ground.
All properties
- Chemical formula
- K₂Cr₂O₇
- Mohs hardness
- 2.5
- Density
- 2.69 g/cm³
- Colors
- Streak
- Yellowish-orange
- Luster
- Vitreous
- Transparency
- Transparent
- Crystal system
- Triclinic
- Crystal habit
- Tabular Crystals, Crusts, Or Granular
- Cleavage
- Distinct On {100}
- Rarity
- Rare
- Uses
- Collector
- Host rock
- Nitrate Deposits in Arid Regions
- Typical price
- $50-500 depending on specimen size and clarity
Where rockhounds find lópezite
Classic worldwide localities
- Chiu-Chiu, Chile
- Iquique, Chile
- Antofagasta, Chile
Field-hunting tip
Look in nitrate deposits in arid regions country, the host setting where lópezite typically forms. If you start seeing nitratine, halite, dietzeite in float, you are in the right ground. Field specimens usually show a tabular crystals, crusts, or granular habit, so train your eye for that shape before scanning the outcrop.
Common questions
How do you identify lópezite?+
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How much is lópezite worth?+
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What rocks look like lópezite?+
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Find lópezite on the map
RockHoundR shows mapped rockhounding spots, access rules, and lets you log every find.
