Brandholzite is a very rare magnesium-antimony hydroxide mineral typically found as small, fragile crystals in hydrothermal ore deposits. It is named after its type locality in Brandholz, Germany, and is primarily of interest to advanced mineralogists and systematic collectors.
Is this brandholzite?
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 brandholzite with a known reference. Brandholzite sits at Mohs 2-3, softer than the next harder reference, harder than the previous one.
- 2Check the streakDrag the specimen across an unglazed porcelain plate. Streak: white.
- 3Read the lusterHold the specimen under a strong light. Luster: vitreous.
- 4Match the color rangeCompare against the expected color range: colorless.
- 5Look at form & habitCrystal system: trigonal. Typical habit: small prismatic crystals or crusts.
Often confused with
Brandholzite vs. its common look-alikes, and how to tell them apart in the field.
How to tell apart: Streak differs, so Brandholzite leaves white, Stibnite leaves lead-gray; luster reads vitreous on Brandholzite and metallic, splendent on cleavage surfaces on Stibnite.
How to tell apart: Luster reads vitreous on Brandholzite and resinous to subadamantine on Senarmontite.
Often found alongside brandholzite
Minerals reported to co-occur with brandholzite. Spotting these in float or country rock is a strong cue you are in the right ground.
All properties
- Chemical formula
- MgSb₂(OH)₁₂·6H₂O
- Mohs hardness
- 2-3
- Density
- 2.65 g/cm³
- Colors
- Streak
- White
- Luster
- Vitreous
- Transparency
- Transparent
- Crystal system
- Trigonal
- Crystal habit
- Small prismatic crystals or crusts
- Cleavage
- None
- Rarity
- Rare
- Uses
- Collector
- Host rock
- From oxidized portions of hydrothermal gold-antimony-quartz veins
Where rockhounds find brandholzite
Classic worldwide localities
- Schmidten-Schacht and Jakobi-Schacht pits of the master lode (the Fürstenzeche), Brandholz-Goldkronach mining district, Fichtelgebirge, Bavaria, Germany (type locality)
- Pernek-Krížnica, near Pernek, Malé Karpaty Mountains, Slovak Republic
- Reported from an abandoned antimony mine in Goesdorf, Luxembourg
Field-hunting tip
Where it forms: From oxidized portions of hydrothermal gold-antimony-quartz veins. If you start seeing stibnite and antimony-ochers, roméite-like phases, sulfur in float, you are in the right ground. Typical habit: small prismatic crystals or crusts. Train your eye for that shape before scanning the outcrop.
Common questions
How do you identify brandholzite?+
Where is brandholzite found?+
Is brandholzite safe to handle?+
What rocks look like brandholzite?+
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Find brandholzite on the map
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