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. Darapskite leaves a white streak.
- 3Read the lusterHold the specimen under a strong light. Darapskite typically shows a vitreous luster.
- 4Match the color rangeCompare against the expected color range: colorless, white, yellowish.
- 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
- 2.2 g/cm³
- Streak
- White
- Luster
- Vitreous
- Transparency
- Transparent
- Crystal system
- Monoclinic
- Crystal habit
- Tabular Crystals, Granular Aggregates, Efflorescent Crusts
- Cleavage
- Perfect On {001}
- Rarity
- Rare
- Uses
- Collector
- Host rock
- Arid Saline Environments and Nitrate Deposits
- Typical price
- $20-100 thumbnail
Where rockhounds find darapskite
Classic worldwide localities
- Atacama Desert, Chile
- Antofagasta, Chile
- Tarapacá, Chile
Field-hunting tip
Look in arid saline environments and nitrate deposits country — that is the host setting where darapskite typically forms. If you start seeing nitratine, halite, gypsum in float, you are in the right ground. Field specimens usually show a tabular crystals, granular aggregates, efflorescent crusts habit, so train your eye for that shape before scanning the outcrop.





