Shigaite is a rare hydrated sulfate mineral that typically forms vibrant, honey-yellow hexagonal plates or rosettes. It is most famous among collectors for specimens found in the manganese mines of Japan and the rare mineral-rich alkaline rocks of Mont Saint-Hilaire, Canada. Collectors should handle these specimens with care, as the mineral is prone to dehydration and damage due to its high water content.
Is this shigaite?
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 shigaite with a known reference. Shigaite sits at Mohs 2.5 — softer than the next harder reference, harder than the previous one.
- 2Check the streakDrag the specimen across an unglazed porcelain plate. Shigaite leaves a white streak.
- 3Read the lusterHold the specimen under a strong light. Shigaite typically shows a vitreous luster.
- 4Match the color rangeCompare against the expected color range: yellow, golden yellow, orange yellow.
- 5Look at form & habitCrystal system: trigonal. Typical habit: tabular crystals, hexagonal plates, rosettes.
Often confused with
Shigaite vs. its common look-alikes — and how to tell them apart in the field.
Often found alongside shigaite
Minerals reported to co-occur with shigaite. Spotting these in float or country rock is a strong cue you are in the right ground.
All properties
- Chemical formula
- NaAl₃(Mn²⁺,Mg,Fe²⁺)₆(SO₄)₂(OH)₁₂·12H₂O
- Mohs hardness
- 2.5
- Density
- 2.05 g/cm³
- Streak
- White
- Luster
- Vitreous
- Transparency
- Transparent
- Crystal system
- Trigonal
- Crystal habit
- Tabular Crystals, Hexagonal Plates, Rosettes
- Cleavage
- Perfect Basal
- Rarity
- Rare
- Uses
- Collector
- Host rock
- Metamorphic Manganese Deposits and Alkaline Igneous Complexes
- Typical price
- $50-300 depending on specimen size and clarity
Where rockhounds find shigaite
Classic worldwide localities
- Shiga Prefecture, Japan
- Mont Saint-Hilaire, Quebec, Canada
- Kalahari Manganese Fields, South Africa
Field-hunting tip
Look in metamorphic manganese deposits and alkaline igneous complexes country — that is the host setting where shigaite typically forms. If you start seeing rhodochrosite, hausmannite, manganite in float, you are in the right ground. Field specimens usually show a tabular crystals, hexagonal plates, rosettes habit, so train your eye for that shape before scanning the outcrop.
Common questions
How do you identify shigaite?+
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Find shigaite on the map
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