Guidottiite is a rare manganese-dominant member of the serpentine subgroup. It typically forms microscopic platy or fibrous layers in hydrothermal veins associated with manganese deposits, often requiring analytical methods for definitive identification.
Is this guidottiite?
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 guidottiite with a known reference. Guidottiite 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. Guidottiite leaves a white streak.
- 3Read the lusterHold the specimen under a strong light. Guidottiite typically shows a waxy luster.
- 4Match the color rangeCompare against the expected color range: green, yellow-green.
- 5Look at form & habitCrystal system: trigonal. Typical habit: platy or fibrous aggregates.
Often confused with
Guidottiite vs. its common look-alikes — and how to tell them apart in the field.
How to tell apart: Luster reads waxy on Guidottiite and silky on Chrysotile.
How to tell apart: Luster reads waxy on Guidottiite and greasy on Lizardite.
How to tell apart: Luster reads waxy on Guidottiite and greasy on Antigorite.
Often found alongside guidottiite
Minerals reported to co-occur with guidottiite. Spotting these in float or country rock is a strong cue you are in the right ground.
All properties
- Chemical formula
- (Mn²⁺,Mg,Fe²⁺)₂Si₂O₅(OH)₄
- Mohs hardness
- 2.5
- Density
- 2.7-2.8 g/cm³
- Colors
- Streak
- White
- Luster
- Waxy
- Transparency
- Translucent
- Crystal system
- Trigonal
- Crystal habit
- Platy or Fibrous Aggregates
- Cleavage
- Perfect Basal
- Rarity
- Rare
- Uses
- Collector
- Host rock
- Manganese-rich Metamorphic Rocks
- Typical price
- $50-300 per specimen
Where rockhounds find guidottiite
Classic worldwide localities
- Tetsuseki mine, Japan
- Cerchiara mine, Italy
- Woods mine, Australia
Field-hunting tip
Look in manganese-rich metamorphic rocks country — that is the host setting where guidottiite typically forms. If you start seeing rhodochrosite, braunite, bustamite in float, you are in the right ground. Field specimens usually show a platy or fibrous aggregates habit, so train your eye for that shape before scanning the outcrop.
Common questions
How do you identify guidottiite?+
Where is guidottiite found?+
How much is guidottiite worth?+
What rocks look like guidottiite?+
What minerals are found with guidottiite?+
What kind of rock does guidottiite form in?+
What is guidottiite used for?+
Find guidottiite on the map
RockHoundR shows mapped rockhounding spots, access rules, and lets you log every find.
