Prachařite is a rare calcium antimony arsenic oxide. It was approved as a distinct mineral species in 2018. It was first described from Plaka Mine No. 80, Plaka, Lavrion District, Attikí Prefecture, Greece.
Is this prachařite?
4-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 prachařite with a known reference. Prachařite sits at Mohs 2, softer than the next harder reference, harder than the previous one.
- 2Read the lusterHold the specimen under a strong light. Luster: resinous.
- 3Match the color rangeCompare against the expected color range: yellow, brownish-yellow.
- 4Look at form & habitCrystal system: trigonal. Typical habit: platy crystals, crusts.
Often confused with
Prachařite vs. its common look-alikes, and how to tell them apart in the field.
How to tell apart: Eskebornite is the harder of the two (Mohs 3-3.5 vs. 2); luster reads resinous on Prachařite and metallic on Eskebornite.
How to tell apart: Luster reads resinous on Prachařite and metallic on Clausthalite.
All properties
- Chemical formula
- CaSb⁵⁺₂(As³⁺₂O₅)₂O₂(H₂O)₇·3H₂O
- Mohs hardness
- 2
- Density
- 4.92 g/cm³
- Colors
- Luster
- Resinous
- Transparency
- Translucent
- Crystal system
- Trigonal
- Crystal habit
- Platy crystals, crusts
- Rarity
- Rare
- Uses
- Collector
- Host rock
- hydrothermal veins
Where rockhounds find prachařite
Classic worldwide localities
- Plaka Mine No. 80, Plaka, Lavrion District, Attikí Prefecture, Greece
Field-hunting tip
Where it forms: hydrothermal veins. If you start seeing plaka, lavrion district, attikí prefecture in float, you are in the right ground. Typical habit: platy crystals, crusts. Train your eye for that shape before scanning the outcrop.
Common questions
How do you identify prachařite?+
Where is prachařite found?+
Is prachařite safe to handle?+
What rocks look like prachařite?+
What minerals are found with prachařite?+
What kind of rock does prachařite form in?+
What is prachařite used for?+
Find prachařite on the map
RockHoundR shows mapped rockhounding spots, access rules, and lets you log every find.
