Siwaqaite is a rare member of the ettringite group typically found as delicate, needle-like acicular crystals. It is primarily known from the Siwaqa area of Jordan, where it forms in highly specific geological settings involving thermal metamorphism. Collectors should handle specimens with care due to their fragility and susceptibility to dehydration.
Is this siwaqaite?
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 siwaqaite with a known reference. Siwaqaite sits at Mohs 3 — softer than the next harder reference, harder than the previous one.
- 2Check the streakDrag the specimen across an unglazed porcelain plate. Siwaqaite leaves a white streak.
- 3Read the lusterHold the specimen under a strong light. Siwaqaite typically shows a vitreous luster.
- 4Match the color rangeCompare against the expected color range: white, colorless.
- 5Look at form & habitCrystal system: hexagonal. Typical habit: acicular crystals.
Often confused with
Siwaqaite vs. its common look-alikes — and how to tell them apart in the field.
Often found alongside siwaqaite
Minerals reported to co-occur with siwaqaite. Spotting these in float or country rock is a strong cue you are in the right ground.
All properties
- Chemical formula
- Ca₆Al₂(SO₄)₃(OH)₁₂·26H₂O
- Mohs hardness
- 3
- Density
- 1.74 g/cm³
- Streak
- White
- Luster
- Vitreous
- Transparency
- Transparent
- Crystal system
- Hexagonal
- Crystal habit
- Acicular Crystals
- Cleavage
- Perfect On {10-10}
- Rarity
- Rare
- Uses
- Collector
- Host rock
- Metamorphic Rocks
- Typical price
- $50-200 thumbnail
Where rockhounds find siwaqaite
Classic worldwide localities
- Siwaqa, Jordan
Field-hunting tip
Look in metamorphic rocks country — that is the host setting where siwaqaite typically forms. If you start seeing ettringite, portlandite, calcite in float, you are in the right ground. Field specimens usually show a acicular crystals habit, so train your eye for that shape before scanning the outcrop.
Common questions
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Find siwaqaite on the map
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