Ruifrancoite is a rare phosphate mineral primarily found in granitic pegmatites. It typically occurs as small tabular crystals associated with other phosphate minerals, often requiring microscopic examination for positive identification due to its similarity to other members of the fillowite group.
Is this ruifrancoite?
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 ruifrancoite with a known reference. Ruifrancoite sits at Mohs 4 — softer than the next harder reference, harder than the previous one.
- 2Check the streakDrag the specimen across an unglazed porcelain plate. Ruifrancoite leaves a white streak.
- 3Read the lusterHold the specimen under a strong light. Ruifrancoite typically shows a vitreous luster.
- 4Match the color rangeCompare against the expected color range: yellow, yellow-brown.
- 5Look at form & habitCrystal system: monoclinic. Typical habit: tabular crystals.
Often confused with
Ruifrancoite vs. its common look-alikes — and how to tell them apart in the field.
Often found alongside ruifrancoite
Minerals reported to co-occur with ruifrancoite. Spotting these in float or country rock is a strong cue you are in the right ground.
All properties
- Chemical formula
- Ca₂Mn₂Ca(PO₄)₃F
- Mohs hardness
- 4
- Density
- 3.58 g/cm³
- Colors
- Streak
- White
- Luster
- Vitreous
- Transparency
- Translucent
- Crystal system
- Monoclinic
- Crystal habit
- Tabular Crystals
- Cleavage
- None
- Rarity
- Rare
- Uses
- Collector
- Host rock
- Granite Pegmatites
- Typical price
- $50-300 per specimen
Where rockhounds find ruifrancoite
Classic worldwide localities
- Tip Top mine, Custer, South Dakota, USA
Field-hunting tip
Look in granite pegmatites country — that is the host setting where ruifrancoite typically forms. If you start seeing quartz, muscovite, albite in float, you are in the right ground. Field specimens usually show a tabular crystals habit, so train your eye for that shape before scanning the outcrop.
Common questions
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Find ruifrancoite on the map
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