Millosevichite is a rare sulfate mineral typically found as a volcanic efflorescence or crust near active fumaroles. Collectors usually find it as a delicate, powdery, or earthy mass that is highly susceptible to humidity and water, often requiring airtight storage.
Is this millosevichite?
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 millosevichite with a known reference. Millosevichite sits at Mohs 1.5, softer than the next harder reference, harder than the previous one.
- 2Check the streakDrag the specimen across an unglazed porcelain plate. Streak: red.
- 3Read the lusterHold the specimen under a strong light. Luster: vitreous.
- 4Match the color rangeCompare against the expected color range: red, clear red, brick red.
- 5Look at form & habitCrystal system: trigonal. Typical habit: encrustations, granular, powdery efflorescence.
Often confused with
Millosevichite vs. its common look-alikes, and how to tell them apart in the field.
How to tell apart: Coquimbite is the harder of the two (Mohs 2.5 vs. 1.5); streak differs, so Millosevichite leaves red, Coquimbite leaves white.
How to tell apart: Streak differs, so Millosevichite leaves red, Halotrichite leaves white.
How to tell apart: Streak differs, so Millosevichite leaves red, Melanterite leaves white.
Often found alongside millosevichite
Minerals reported to co-occur with millosevichite. Spotting these in float or country rock is a strong cue you are in the right ground.
All properties
- Chemical formula
- Al₂(SO₄)₃
- Mohs hardness
- 1.5
- Density
- 1.72 g/cm³
- Colors
- Streak
- Red
- Luster
- Vitreous
- Transparency
- Semitransparent
- Crystal system
- Trigonal
- Crystal habit
- Encrustations, granular, powdery efflorescence
- Cleavage
- None
- Rarity
- Rare
- Uses
- Collector
- Host rock
- Precipitated at high temperature from gasses originating from solfataric activity or burning coal measures
Where rockhounds find millosevichite
Classic worldwide localities
- Shamokin, near Burnside, Northumberland Co., Pennsylvania, USA
- Alum Grotto, Vulcano, Lipari Islands, Italy
- Velikomostov-3 coal mine, L’vov-Volyn’ Basin, Ukraine
- Schoeller coal mine, Libušin, near Kladno, Czech Republic
- Miskolc-Lyukóbánya, Hungary
Field-hunting tip
Where it forms: Precipitated at high temperature from gasses originating from solfataric activity or burning coal measures. If you start seeing sulfur, sal ammoniac, letovicite in float, you are in the right ground. Typical habit: encrustations, granular, powdery efflorescence. Train your eye for that shape before scanning the outcrop.
Common questions
How do you identify millosevichite?+
Where is millosevichite found?+
What rocks look like millosevichite?+
What minerals are found with millosevichite?+
What kind of rock does millosevichite form in?+
What is millosevichite used for?+
Find millosevichite on the map
RockHoundR shows mapped rockhounding spots, access rules, and lets you log every find.
