Bosoite is a silicate, typically colorless. It formed under low-temperature conditions during diagenesis of tuffaceous forearc sandstone and mudstone. Associated minerals include chibaite, quartz and calcite. It was first described from Arakawa, Minami-boso City, Chiba Prefecture, Japan.
Is this bosoite?
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 bosoite with a known reference. Bosoite sits at Mohs 6.5-7, softer than the next harder reference, harder than the previous one.
- 2Check the streakDrag the specimen across an unglazed porcelain plate. Bosoite leaves a white streak.
- 3Read the lusterHold the specimen under a strong light. Bosoite typically shows a vitreous luster.
- 4Match the color rangeCompare against the expected color range: colorless.
- 5Look at form & habitCrystal system: hexagonal. Typical habit: massive, crusts, or globular aggregates.
Often confused with
Bosoite vs. its common look-alikes, and how to tell them apart in the field.
How to tell apart: Streak differs, so Bosoite leaves white, Romanèchite leaves shiny brownish black; luster reads vitreous on Bosoite and submetallic to dull on Romanèchite.
How to tell apart: Streak differs, so Bosoite leaves white, Pyrolusite leaves black; luster reads vitreous on Bosoite and metallic on Pyrolusite.
Often found alongside bosoite
Minerals reported to co-occur with bosoite. Spotting these in float or country rock is a strong cue you are in the right ground.
All properties
- Chemical formula
- SiO₂·nCₓH₂ₓ₊₂
- Mohs hardness
- 6.5-7
- Density
- 2.04 g/cm³
- Colors
- Streak
- White
- Luster
- Vitreous
- Transparency
- Transparent
- Crystal system
- Hexagonal
- Crystal habit
- Massive, Crusts, Or Globular Aggregates
- Cleavage
- None
- Rarity
- Common
- Uses
- Collector
- Host rock
- Sedimentary Manganese Deposits
Where rockhounds find bosoite
Classic worldwide localities
- Boso Peninsula, Japan
- Various sedimentary manganese deposits globally
Field-hunting tip
Look in sedimentary manganese deposits country, the host setting where bosoite typically forms. If you start seeing quartz, calcite, goethite in float, you are in the right ground. Field specimens usually show a massive, crusts, or globular aggregates habit, so train your eye for that shape before scanning the outcrop.
Common questions
How do you identify bosoite?+
Where is bosoite found?+
What rocks look like bosoite?+
What minerals are found with bosoite?+
What kind of rock does bosoite form in?+
What is bosoite used for?+
Find bosoite on the map
RockHoundR shows mapped rockhounding spots, access rules, and lets you log every find.
