Sanbornite is a rare barium silicate mineral primarily known from the metamorphic deposits of the Big Creek area in California. Collectors look for its characteristic bright orange fluorescence under ultraviolet light and its presence in complex barium-rich assemblages.
Is this sanbornite?
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 sanbornite with a known reference. Sanbornite sits at Mohs 5, 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: pearly.
- 4Match the color rangeCompare against the expected color range: colorless, white.
- 5Look at form & habitCrystal system: orthorhombic. Typical habit: platy.
Often confused with
Sanbornite vs. its common look-alikes, and how to tell them apart in the field.
How to tell apart: Luster reads pearly on Sanbornite and vitreous, pearly on cleavage on Wollastonite.
How to tell apart: Sanbornite is noticeably harder (Mohs 5 vs. 3-3.5); luster reads pearly on Sanbornite and vitreous to resinous, may be pearly on Barite.
Often found alongside sanbornite
Minerals reported to co-occur with sanbornite. Spotting these in float or country rock is a strong cue you are in the right ground.
All properties
- Chemical formula
- BaSi₂O₅
- Mohs hardness
- 5
- Density
- 3.70 g/cm³
- Streak
- White
- Luster
- Pearly
- Transparency
- Semitransparent
- Crystal system
- Orthorhombic
- Crystal habit
- Platy
- Cleavage
- Perfect on {001}; imperfect on {100} and {010}
- Fluorescence
- Bright orange under SW and LW UV
- Rarity
- Rare
- Uses
- Collector, Scientific research
- Host rock
- In veins in metamorphosed sediments, largely quartzites and hornfels (Trumbull Peak, California, USA)
Where rockhounds find sanbornite
Classic worldwide localities
- Trumbull Peak, near Incline, Mariposa Co., California, USA
- Gunn claim, Itsy Mountains, near Macmillan Pass, Yukon Territory, Canada
Field-hunting tip
Where it forms: In veins in metamorphosed sediments, largely quartzites and hornfels (Trumbull Peak, California, USA). If you start seeing quartz, gillespite, diopside in float, you are in the right ground. Typical habit: platy. Train your eye for that shape before scanning the outcrop.
Common questions
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Find sanbornite on the map
RockHoundR shows mapped rockhounding spots, access rules, and lets you log every find.
