Silvialite is a rare sulfate-rich member of the scapolite group, typically found in high-grade metamorphic rocks. It is visually indistinguishable from other scapolites without chemical analysis, though its specific sulfate content is its defining characteristic. Collectors typically find it in small, prismatic crystals within calc-silicate assemblages.
Is this silvialite?
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 silvialite with a known reference. Silvialite 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. Silvialite leaves a white streak.
- 3Read the lusterHold the specimen under a strong light. Silvialite typically shows a vitreous luster.
- 4Match the color rangeCompare against the expected color range: white, colorless, gray.
- 5Look at form & habitCrystal system: tetragonal. Typical habit: prismatic crystals.
Often confused with
Silvialite vs. its common look-alikes — and how to tell them apart in the field.
Often found alongside silvialite
Minerals reported to co-occur with silvialite. Spotting these in float or country rock is a strong cue you are in the right ground.
All properties
- Chemical formula
- (Ca,Na)₄(Si,Al)₁₂O₂₄(SO₄,CO₃)
- Mohs hardness
- 5-6
- Density
- 2.68-2.73 g/cm³
- Streak
- White
- Luster
- Vitreous
- Transparency
- Transparent
- Crystal system
- Tetragonal
- Crystal habit
- Prismatic Crystals
- Cleavage
- Distinct On {100} and {110}
- Fluorescence
- Orange Under SW UV
- Rarity
- Rare
- Uses
- Collector
- Host rock
- Metamorphosed Limestone or Calc-silicate Rocks
- Typical price
- $20-150 thumbnail
Where rockhounds find silvialite
Classic worldwide localities
- Malsburg, Germany
- Grenville Province, Canada
- Pargas, Finland
Field-hunting tip
Look in metamorphosed limestone or calc-silicate rocks country — that is the host setting where silvialite typically forms. If you start seeing calcite, diopside, garnet in float, you are in the right ground. Field specimens usually show a prismatic crystals habit, so train your eye for that shape before scanning the outcrop.
Common questions
How do you identify silvialite?+
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How much is silvialite worth?+
What rocks look like silvialite?+
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Find silvialite on the map
RockHoundR shows mapped rockhounding spots, access rules, and lets you log every find.
