Yazganite is a rare sulfate mineral typically found as small, brown to brown-black, tabular crystals in oxidized hydrothermal environments. It is chemically related to the jarosite group and is highly prized by mineral collectors due to its extremely limited type locality in Turkey.
Is this yazganite?
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 yazganite with a known reference. Yazganite sits at Mohs 5, softer than the next harder reference, harder than the previous one.
- 2Check the streakDrag the specimen across an unglazed porcelain plate. Streak: bright brown to yellow-gray.
- 3Read the lusterHold the specimen under a strong light. Luster: adamantine.
- 4Match the color rangeCompare against the expected color range: brown, brownish black.
- 5Look at form & habitCrystal system: monoclinic. Typical habit: aggregates, euhedral crystals, prismatic.
Often confused with
Yazganite vs. its common look-alikes, and how to tell them apart in the field.
How to tell apart: Yazganite is noticeably harder (Mohs 5 vs. 2.5-3.5); streak differs, so Yazganite leaves bright brown to yellow-gray, Jarosite leaves pale yellow; luster reads adamantine on Yazganite and subadamantine to vitreous, resinous on fractures on Jarosite.
How to tell apart: Yazganite is noticeably harder (Mohs 5 vs. 3); streak differs, so Yazganite leaves bright brown to yellow-gray, Natrojarosite leaves light yellow; luster reads adamantine on Yazganite and vitreous on Natrojarosite.
Often found alongside yazganite
Minerals reported to co-occur with yazganite. Spotting these in float or country rock is a strong cue you are in the right ground.
All properties
- Chemical formula
- ☐NaMgFe³⁺₂(AsO₄)₃·H₂O
- Mohs hardness
- 5
- Density
- 4.18 g/cm³
- Colors
- Streak
- Bright brown to yellow-gray
- Luster
- Adamantine
- Transparency
- Translucent
- Crystal system
- Monoclinic
- Crystal habit
- Aggregates, euhedral crystals, prismatic
- Cleavage
- None
- Rarity
- Rare
- Uses
- Collector
- Host rock
- A hydrothermal mineral in fissures cutting porphyritic andesite in a stratovolcano
Where rockhounds find yazganite
Classic worldwide localities
- Erciyes stratovolcanic complex, 10 km south of the prefecture of Kayseri, near Hisarcik, Kiranardi, Turkey
Field-hunting tip
Where it forms: A hydrothermal mineral in fissures cutting porphyritic andesite in a stratovolcano. If you start seeing cassiterite, hematite, magnetite in float, you are in the right ground. Typical habit: aggregates, euhedral crystals, prismatic. Train your eye for that shape before scanning the outcrop.
Common questions
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Find yazganite on the map
RockHoundR shows mapped rockhounding spots, access rules, and lets you log every find.
