Sinjarite is a rare hydrous calcium chloride mineral that typically forms as efflorescent crusts or fibrous aggregates in extremely arid environments. Because it is highly deliquescent and soluble in water, it must be stored in a sealed, humidity-controlled environment to prevent it from absorbing moisture from the air and dissolving.
Is this sinjarite?
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 sinjarite with a known reference. Sinjarite sits at Mohs 1.5, 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 to resinous.
- 4Match the color rangeCompare against the expected color range: light pink.
- 5Look at form & habitCrystal system: tetragonal. Typical habit: deliquescent, massive, prismatic.
Often confused with
Sinjarite vs. its common look-alikes, and how to tell them apart in the field.
Often found alongside sinjarite
Minerals reported to co-occur with sinjarite. Spotting these in float or country rock is a strong cue you are in the right ground.
All properties
- Chemical formula
- CaCl₂·2H₂O
- Mohs hardness
- 1.5
- Density
- 1.66 g/cm³
- Colors
- Streak
- White
- Luster
- Vitreous to resinous
- Transparency
- Semitransparent
- Crystal system
- Tetragonal
- Crystal habit
- Deliquescent, massive, prismatic
- Cleavage
- Prismatic, good
- Rarity
- Rare
- Uses
- Collector
- Host rock
- In a dry stream bed, apparently precipitated from groundwater
Where rockhounds find sinjarite
Classic worldwide localities
- Sinjar, W of Mosul, Iraq (type locality)
Field-hunting tip
Where it forms: In a dry stream bed, apparently precipitated from groundwater. If you start seeing halite, gypsum in float, you are in the right ground. Typical habit: deliquescent, massive, prismatic. Train your eye for that shape before scanning the outcrop.
Common questions
How do you identify sinjarite?+
Where is sinjarite found?+
What rocks look like sinjarite?+
What minerals are found with sinjarite?+
What kind of rock does sinjarite form in?+
What is sinjarite used for?+
Find sinjarite on the map
RockHoundR shows mapped rockhounding spots, access rules, and lets you log every find.
