Matsubaraite is a rare strontium-titanium silicate belonging to the chevkinite group. It is typically found as small, dark brown to black tabular crystals associated with glaucophane schist formations. It is primarily a collector's mineral known for its complex chemical structure and limited type locality in Japan.
Is this matsubaraite?
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 matsubaraite with a known reference. Matsubaraite 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. Matsubaraite leaves a light brown streak.
- 3Read the lusterHold the specimen under a strong light. Matsubaraite typically shows a vitreous luster.
- 4Match the color rangeCompare against the expected color range: brown, black.
- 5Look at form & habitCrystal system: monoclinic. Typical habit: tabular crystals, subhedral grains.
Often found alongside matsubaraite
Minerals reported to co-occur with matsubaraite. Spotting these in float or country rock is a strong cue you are in the right ground.
All properties
- Chemical formula
- Sr₄Ti₅(Si₂O₇)₂O₈
- Mohs hardness
- 5-6
- Density
- 4.45 g/cm³
- Streak
- Light Brown
- Luster
- Vitreous
- Transparency
- Opaque
- Crystal system
- Monoclinic
- Crystal habit
- Tabular Crystals, Subhedral Grains
- Cleavage
- None
- Rarity
- Rare
- Uses
- Collector
- Host rock
- Glaucophane Schists
- Typical price
- $50-300 per specimen depending on size
Where rockhounds find matsubaraite
Classic worldwide localities
- Itoigawa, Niigata Prefecture, Japan
Field-hunting tip
Look in glaucophane schists country — that is the host setting where matsubaraite typically forms. If you start seeing benitoite, joaquinite, ortho-joaquinite in float, you are in the right ground. Field specimens usually show a tabular crystals, subhedral grains habit, so train your eye for that shape before scanning the outcrop.
Common questions
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Find matsubaraite on the map
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