Fluoro-richterite is a relatively rare member of the amphibole group found primarily in contact-metamorphosed limestones and skarns. It typically forms elongate, prismatic, or fibrous crystals that are often difficult to distinguish from tremolite without chemical analysis.
Is this fluoro-richterite?
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 fluoro-richterite with a known reference. Fluoro-richterite sits at Mohs 5-6, softer than the next harder reference, harder than the previous one.
- 2Check the streakDrag the specimen across an unglazed porcelain plate. Fluoro-richterite leaves a white streak.
- 3Read the lusterHold the specimen under a strong light. Fluoro-richterite typically shows a vitreous luster.
- 4Match the color rangeCompare against the expected color range: white, brown, yellow, colorless.
- 5Look at form & habitCrystal system: monoclinic. Typical habit: prismatic crystals, fibrous, columnar.
Often confused with
Fluoro-richterite vs. its common look-alikes, and how to tell them apart in the field.
How to tell apart: Luster reads vitreous on Fluoro-richterite and vitreous to silky on Actinolite.
How to tell apart: Streak differs, so Fluoro-richterite leaves white, Richterite leaves pale yellow.
Often found alongside fluoro-richterite
Minerals reported to co-occur with fluoro-richterite. Spotting these in float or country rock is a strong cue you are in the right ground.
All properties
- Chemical formula
- Na(NaCa)Mg₅Si₈O₂₂(F,OH)₂
- Mohs hardness
- 5-6
- Density
- 3.0-3.1 g/cm³
- Streak
- White
- Luster
- Vitreous
- Transparency
- Translucent
- Crystal system
- Monoclinic
- Crystal habit
- Prismatic Crystals, Fibrous, Columnar
- Cleavage
- Perfect Prismatic
- Rarity
- Rare
- Uses
- Collector
- Host rock
- Metamorphic Limestones, Skarns
Where rockhounds find fluoro-richterite
Classic worldwide localities
- Kola Peninsula, Russia
- Grenville Province, Canada
- Sweden
- New York, USA
Field-hunting tip
Look in metamorphic limestones, skarns country, the host setting where fluoro-richterite typically forms. If you start seeing diopside, calcite, phlogopite in float, you are in the right ground. Field specimens usually show a prismatic crystals, fibrous, columnar habit, so train your eye for that shape before scanning the outcrop.
Common questions
How do you identify fluoro-richterite?+
Where is fluoro-richterite found?+
What rocks look like fluoro-richterite?+
What minerals are found with fluoro-richterite?+
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Find fluoro-richterite on the map
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