Ganomalite is a rare lead-calcium silicate mineral typically found in metamorphosed manganese deposits. It usually occurs as massive, granular aggregates or small tabular crystals and is highly sought after by collectors of rare lead species.
Is this ganomalite?
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 ganomalite with a known reference. Ganomalite sits at Mohs 3, 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: resinous to vitreous.
- 4Match the color rangeCompare against the expected color range: colorless, gray, white.
- 5Look at form & habitCrystal system: trigonal. Typical habit: massive, prismatic.
Often confused with
Ganomalite vs. its common look-alikes, and how to tell them apart in the field.
How to tell apart: Luster reads resinous to vitreous on Ganomalite and pearly on cleavage on Margarosanite.
How to tell apart: Nasonite is the harder of the two (Mohs 4 vs. 3); luster reads resinous to vitreous on Ganomalite and greasy to adamantine on Nasonite.
Often found alongside ganomalite
Minerals reported to co-occur with ganomalite. Spotting these in float or country rock is a strong cue you are in the right ground.
All properties
- Chemical formula
- Pb₉Ca₅(Si₂O₇)₃(SiO₄)O₁₋₂
- Mohs hardness
- 3
- Density
- 5.7 g/cm³
- Streak
- White
- Luster
- Resinous to vitreous
- Transparency
- Semitransparent
- Crystal system
- Trigonal
- Crystal habit
- Massive, prismatic
- Cleavage
- {1010} and {0001}, distinct
- Rarity
- Rare
- Uses
- Collector
- Host rock
- In skarn assemblages (Jakobsberg, Sweden); in manganese ores in a metamorphosed stratiform zinc orebody (Franklin, New Jersey, USA)
Where rockhounds find ganomalite
Classic worldwide localities
- Franklin, Sussex Co., New Jersey, USA
- Långban, in the Harstigen mine, near Persberg, and at Jakobsberg, Värmland, Sweden
Field-hunting tip
Where it forms: In skarn assemblages (Jakobsberg, Sweden); in manganese ores in a metamorphosed stratiform zinc orebody (Franklin, New Jersey, USA). If you start seeing tephroite, lead, jacobsite in float, you are in the right ground. Typical habit: massive, prismatic. Train your eye for that shape before scanning the outcrop.
Common questions
How do you identify ganomalite?+
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Find ganomalite on the map
RockHoundR shows mapped rockhounding spots, access rules, and lets you log every find.
