Koktaite is a rare sulfate mineral that typically forms as white to colorless efflorescences or small, thin tabular crystals in self-burning coal mine waste heaps. It is chemically related to syngenite but contains ammonium as a major cation, making it a distinct phase often found in ephemeral environments. Due to its solubility, it is best kept in a dry environment and protected from high humidity.
Is this koktaite?
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 koktaite with a known reference. Koktaite sits at Mohs 2, softer than the next harder reference, harder than the previous one.
- 2Check the streakDrag the specimen across an unglazed porcelain plate. Koktaite leaves a white streak.
- 3Read the lusterHold the specimen under a strong light. Koktaite typically shows a vitreous luster.
- 4Match the color rangeCompare against the expected color range: colorless, white.
- 5Look at form & habitCrystal system: monoclinic. Typical habit: tabular crystals, crusts, efflorescences.
Often confused with
Koktaite vs. its common look-alikes, and how to tell them apart in the field.
Often found alongside koktaite
Minerals reported to co-occur with koktaite. Spotting these in float or country rock is a strong cue you are in the right ground.
All properties
- Chemical formula
- (NH₄)₂Ca(SO₄)₂·H₂O
- Mohs hardness
- 2
- Density
- 2.09 g/cm³
- Streak
- White
- Luster
- Vitreous
- Transparency
- Translucent
- Crystal system
- Monoclinic
- Crystal habit
- Tabular Crystals, Crusts, Efflorescences
- Cleavage
- Distinct
- Rarity
- Rare
- Uses
- Collector
- Host rock
- Burning Coal Mine Dumps, Guano Deposits
Where rockhounds find koktaite
Classic worldwide localities
- Koktavskoe coal mine, Czech Republic
- various guano deposits
- burning coal waste heaps
Field-hunting tip
Look in burning coal mine dumps, guano deposits country, the host setting where koktaite typically forms. If you start seeing gypsum, syngenite, arcanite in float, you are in the right ground. Field specimens usually show a tabular crystals, crusts, efflorescences habit, so train your eye for that shape before scanning the outcrop.
Common questions
How do you identify koktaite?+
Where is koktaite found?+
What rocks look like koktaite?+
What minerals are found with koktaite?+
What kind of rock does koktaite form in?+
What is koktaite used for?+
Find koktaite on the map
RockHoundR shows mapped rockhounding spots, access rules, and lets you log every find.
