Khaidarkanite is a rare copper aluminium hydroxide fluoride known primarily from its type locality in Kyrgyzstan. It typically forms delicate, pale blue platy or micaceous crystals often coating other minerals in oxidized hydrothermal vein systems.
Is this khaidarkanite?
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 khaidarkanite with a known reference. Khaidarkanite 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: light blue.
- 3Read the lusterHold the specimen under a strong light. Luster: vitreous.
- 4Match the color rangeCompare against the expected color range: bright blue.
- 5Look at form & habitCrystal system: monoclinic. Typical habit: acicular, aggregates, radial.
Often confused with
Khaidarkanite vs. its common look-alikes, and how to tell them apart in the field.
How to tell apart: Streak differs, so Khaidarkanite leaves light blue, Devilline leaves pale green.
How to tell apart: Streak differs, so Khaidarkanite leaves light blue, Posnjakite leaves pale blue.
How to tell apart: Serpierite is the harder of the two (Mohs 3.5-4 vs. ~2.5); streak differs, so Khaidarkanite leaves light blue, Serpierite leaves greenish white.
Often found alongside khaidarkanite
Minerals reported to co-occur with khaidarkanite. Spotting these in float or country rock is a strong cue you are in the right ground.
All properties
- Chemical formula
- Cu₄Al₃(OH)₁₄F₃·2H₂O
- Mohs hardness
- ~2.5
- Density
- 2.84 g/cm³
- Colors
- Streak
- Light blue
- Luster
- Vitreous
- Transparency
- Translucent
- Crystal system
- Monoclinic
- Crystal habit
- Acicular, aggregates, radial
- Rarity
- Rare
- Uses
- Collector
- Host rock
- Secondary in highly oxidized, copper-bearing, fluorite-rich veinstone that locally evolved small quantities of hydrofluoric acid (HF) during weathering (Great Sled Dale)
Where rockhounds find khaidarkanite
Classic worldwide localities
- Khaidarkan Sb-Hg deposit, Kyrgyzstan (type locality)
- Great Sled Dale, Angram Common, Keld, Swaledale, North Yorkshire, England
Field-hunting tip
Where it forms: Secondary in highly oxidized, copper-bearing, fluorite-rich veinstone that locally evolved small quantities of hydrofluoric acid (HF) during weathering (Great Sled Dale). If you start seeing calcite, quartz, baryte in float, you are in the right ground. Typical habit: acicular, aggregates, radial. Train your eye for that shape before scanning the outcrop.
Common questions
How do you identify khaidarkanite?+
Where is khaidarkanite found?+
Is khaidarkanite safe to handle?+
What rocks look like khaidarkanite?+
What minerals are found with khaidarkanite?+
What kind of rock does khaidarkanite form in?+
What is khaidarkanite used for?+
Find khaidarkanite on the map
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