Sarcopside is a rare phosphate mineral primarily found in complex granitic pegmatites. It typically occurs as massive, lamellar, or granular patches that exhibit a characteristic reddish-brown color, which can alter to a darker brown or black upon oxidation.
Is this sarcopside?
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 sarcopside with a known reference. Sarcopside 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. Streak: white.
- 3Read the lusterHold the specimen under a strong light. Luster: silky to waxy.
- 4Match the color rangeCompare against the expected color range: red, purplish blue, green, reddish brown.
- 5Look at form & habitCrystal system: monoclinic. Typical habit: fibrous.
Often confused with
Sarcopside vs. its common look-alikes, and how to tell them apart in the field.
How to tell apart: Luster reads silky to waxy on Sarcopside and vitreous to subresinous on Triphylite.
How to tell apart: Streak differs, so Sarcopside leaves white, Ludlamite leaves pale greenish white; luster reads silky to waxy on Sarcopside and vitreous, pearly on {001} cleavage on Ludlamite.
Often found alongside sarcopside
Minerals reported to co-occur with sarcopside. Spotting these in float or country rock is a strong cue you are in the right ground.
All properties
- Chemical formula
- Fe₃□(PO₄)₂
- Mohs hardness
- 4
- Density
- 3.79 g/cm³
- Colors
- Streak
- White
- Luster
- Silky to waxy
- Transparency
- Translucent
- Crystal system
- Monoclinic
- Crystal habit
- Fibrous
- Cleavage
- {100}, {001}, good; {010}, poor
- Rarity
- Rare
- Uses
- Collector, Scientific research
- Host rock
- Formed along with graftonite, probably by exsolution from triphylite, in complex zoned granite pegmatites
Where rockhounds find sarcopside
Classic worldwide localities
- Gingrass Farm, near Deering, Hillsboro Co., in the G.E. Smith mine, Newport, Sullivan Co., and from the DeMott and French King No. 2 mines, East Alstead, Cheshire Co., New Hampshire, USA
- Bull Moose and Victory mines, and the Lofton prospect, near Custer, Custer Co., South Dakota, USA
- Góry Sowie (Michelsdorf), in the Eulengebirge, Silesia, Poland
- Otov and Domažlice, Czech Republic
- Norrö pegmatite, on Rånö Island, and in the Berg quarry, near Sollefteå, Västerbotten, Sweden
- Hagendorf, Bavaria, Germany
Field-hunting tip
Where it forms: Formed along with graftonite, probably by exsolution from triphylite, in complex zoned granite pegmatites. If you start seeing graftonite, vivianite, huréaulite in float, you are in the right ground. Typical habit: fibrous. Train your eye for that shape before scanning the outcrop.
Common questions
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Find sarcopside on the map
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