Ungemachite is a rare potassium-sodium-iron sulfate typically found as thin, tabular crystals in arid, oxidized mining environments. It is most recognized for its occurrence in the Chilean nitrate districts, often appearing as small, clear to yellowish hexagonal plates associated with other secondary sulfate minerals.
Is this ungemachite?
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 ungemachite with a known reference. Ungemachite 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. Ungemachite leaves a white streak.
- 3Read the lusterHold the specimen under a strong light. Ungemachite typically shows a vitreous luster.
- 4Match the color rangeCompare against the expected color range: colorless, yellow, white.
- 5Look at form & habitCrystal system: trigonal. Typical habit: tabular crystals, often pseudo-rhombohedral.
Often confused with
Ungemachite vs. its common look-alikes — and how to tell them apart in the field.
Often found alongside ungemachite
Minerals reported to co-occur with ungemachite. Spotting these in float or country rock is a strong cue you are in the right ground.
All properties
- Chemical formula
- K₃Na₈Fe³⁺(SO₄)₆(OH)₂·6H₂O
- Mohs hardness
- 2.5
- Density
- 2.28 g/cm³
- Streak
- White
- Luster
- Vitreous
- Transparency
- Transparent
- Crystal system
- Trigonal
- Crystal habit
- Tabular Crystals, Often Pseudo-rhombohedral
- Cleavage
- Distinct On {0001}
- Rarity
- Rare
- Uses
- Collector
- Host rock
- Oxidized Zones of Pyrite-rich Ore Deposits
- Typical price
- $50-300 per specimen
Where rockhounds find ungemachite
Classic worldwide localities
- Alcaparrosa Mine, Chile
- Chuquicamata, Chile
- Sierra Gorda, Chile
Field-hunting tip
Look in oxidized zones of pyrite-rich ore deposits country — that is the host setting where ungemachite typically forms. If you start seeing metavoltine, copiapite, jarosite in float, you are in the right ground. Field specimens usually show a tabular crystals, often pseudo-rhombohedral habit, so train your eye for that shape before scanning the outcrop.
Common questions
How do you identify ungemachite?+
Where is ungemachite found?+
How much is ungemachite worth?+
What rocks look like ungemachite?+
What minerals are found with ungemachite?+
What kind of rock does ungemachite form in?+
What is ungemachite used for?+
Find ungemachite on the map
RockHoundR shows mapped rockhounding spots, access rules, and lets you log every find.
