Julgoldite-(Fe3+) is a rare member of the pumpellyite group, typically occurring as small, dark, tabular crystals within volcanic rock cavities. Collectors generally find it as part of mineral assemblages in basalt, often associated with secondary minerals like quartz and prehnite.
Is this julgoldite-(fe3+)?
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 julgoldite-(fe3+) with a known reference. Julgoldite-(Fe3+) sits at Mohs 6 — softer than the next harder reference, harder than the previous one.
- 2Check the streakDrag the specimen across an unglazed porcelain plate. Julgoldite-(Fe3+) leaves a brownish streak.
- 3Read the lusterHold the specimen under a strong light. Julgoldite-(Fe3+) typically shows a vitreous luster.
- 4Match the color rangeCompare against the expected color range: black, brownish black.
- 5Look at form & habitCrystal system: monoclinic. Typical habit: tabular crystals, radiating aggregates.
Often confused with
Julgoldite-(Fe3+) vs. its common look-alikes — and how to tell them apart in the field.
Often found alongside julgoldite-(fe3+)
Minerals reported to co-occur with julgoldite-(fe3+). Spotting these in float or country rock is a strong cue you are in the right ground.
All properties
- Chemical formula
- Ca₂Fe₃²⁺(Si₂O₇)(SiO₄)(OH)₂·H₂O
- Mohs hardness
- 6
- Density
- 3.55-3.65 g/cm³
- Colors
- Streak
- Brownish
- Luster
- Vitreous
- Transparency
- Opaque
- Crystal system
- Monoclinic
- Crystal habit
- Tabular Crystals, Radiating Aggregates
- Cleavage
- Poor
- Rarity
- Rare
- Uses
- Collector
- Host rock
- Basaltic Vugs and Cavities
- Typical price
- $20-100 per specimen
Where rockhounds find julgoldite-(fe3+)
Classic worldwide localities
- Bombay, India
- Kallur, India
- Långban, Sweden
Field-hunting tip
Look in basaltic vugs and cavities country — that is the host setting where julgoldite-(fe3+) typically forms. If you start seeing quartz, calcite, prehnite in float, you are in the right ground. Field specimens usually show a tabular crystals, radiating aggregates habit, so train your eye for that shape before scanning the outcrop.
Common questions
How do you identify julgoldite-(fe3+)?+
Where is julgoldite-(fe3+) found?+
How much is julgoldite-(fe3+) worth?+
What rocks look like julgoldite-(fe3+)?+
What minerals are found with julgoldite-(fe3+)?+
What kind of rock does julgoldite-(fe3+) form in?+
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Find julgoldite-(fe3+) on the map
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