Darapskite is a rare hydrous sodium nitrate-sulfate mineral that typically forms in the hyper-arid nitrate fields of the Atacama Desert. Collectors should look for its distinctive tabular crystals or white crusts, often found associated with other rare nitrate minerals in salt flats and evaporite deposits.
Is this darapskite?
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 darapskite with a known reference. Darapskite 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. Streak: white.
- 3Read the lusterHold the specimen under a strong light. Luster: vitreous.
- 4Match the color rangeCompare against the expected color range: colorless.
- 5Look at form & habitCrystal system: monoclinic. Typical habit: tabular crystals, granular aggregates, efflorescent crusts.
Often confused with
Darapskite vs. its common look-alikes, and how to tell them apart in the field.
Often found alongside darapskite
Minerals reported to co-occur with darapskite. Spotting these in float or country rock is a strong cue you are in the right ground.
All properties
- Chemical formula
- Na₃(NO₃)(SO₄)·H₂O
- Mohs hardness
- 2.5
- Density
- 2.201 g/cm³
- Colors
- Streak
- White
- Luster
- Vitreous
- Transparency
- Transparent to translucent
- Crystal system
- Monoclinic
- Crystal habit
- Tabular crystals, granular aggregates, efflorescent crusts
- Cleavage
- On {010} and {100}, perfect
- Rarity
- Rare
- Uses
- Collector
- Host rock
- Widespread in commercial nitrate deposits, filling veins and cavities in cemented regolith, in an arid region (Chile); in saline arid soil (Death Valley, California, USA; Antarctica)
Where rockhounds find darapskite
Classic worldwide localities
- Mineral Mountain mine, south of Stein’s Pass, Peloncillo Mountains, Greenlee Co., Arizona, USA
- Death Valley, Inyo Co., as deposits in soil and in caves in the Funeral Mountains, California, USA
- Flower Cave, southern Big Bend National Park, Texas, USA
- Antofagasta, from Oficina Lautaro, Pampa del Toro, Taltal district, in thick veins from Chuquicamata, and widespread in other nitrate deposits, such as those around Oficinas Alemania, María Elena, Victoria, Santa Lucia, Chile
- Zapiga, Tarapacá, Chile
- Mt. Erebus and in the Wright Valley, Victoria Land, Antarctica
Field-hunting tip
Where it forms: Widespread in commercial nitrate deposits, filling veins and cavities in cemented regolith, in an arid region (Chile); in saline arid soil (Death Valley, California, USA; Antarctica). If you start seeing nitratine, niter, blödite in float, you are in the right ground. Typical habit: tabular crystals, granular aggregates, efflorescent crusts. Train your eye for that shape before scanning the outcrop.
Common questions
How do you identify darapskite?+
Where is darapskite found?+
What rocks look like darapskite?+
What minerals are found with darapskite?+
What kind of rock does darapskite form in?+
What is darapskite used for?+
Find darapskite on the map
RockHoundR shows mapped rockhounding spots, access rules, and lets you log every find.
