Bigcreekite is an extremely rare barium-calcium silicate mineral known almost exclusively from its type locality at the Big Creek drainage in California. It typically occurs as small, colorless, platy, or tabular crystals associated with other rare barium minerals in metamorphic rock environments.
Is this bigcreekite?
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 bigcreekite with a known reference. Bigcreekite 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. Bigcreekite leaves a white streak.
- 3Read the lusterHold the specimen under a strong light. Bigcreekite typically shows a vitreous luster.
- 4Match the color rangeCompare against the expected color range: colorless, white.
- 5Look at form & habitCrystal system: monoclinic. Typical habit: platy crystals.
Often confused with
Bigcreekite vs. its common look-alikes — and how to tell them apart in the field.
How to tell apart: Bigcreekite is noticeably harder (Mohs 3 vs. 2); streak differs — Bigcreekite leaves white, Delrioite leaves yellow.
How to tell apart: Apophyllite is the harder of the two (Mohs 4.5-5 vs. 3); luster reads vitreous on Bigcreekite and vitreous to pearly on Apophyllite.
Often found alongside bigcreekite
Minerals reported to co-occur with bigcreekite. Spotting these in float or country rock is a strong cue you are in the right ground.
All properties
- Chemical formula
- BaCa₂Si₄O₁₀·4H₂O
- Mohs hardness
- 3
- Density
- 2.16 g/cm³
- Streak
- White
- Luster
- Vitreous
- Transparency
- Transparent
- Crystal system
- Monoclinic
- Crystal habit
- Platy Crystals
- Cleavage
- Perfect
- Rarity
- Rare
- Uses
- Collector
- Host rock
- Metamorphosed Limestone Inclusions in Granitic Rock
- Typical price
- $50-500 depending on specimen size
Where rockhounds find bigcreekite
Classic worldwide localities
- Big Creek, Fresno County, California, USA
Field-hunting tip
Look in metamorphosed limestone inclusions in granitic rock country — that is the host setting where bigcreekite typically forms. If you start seeing wickenburgite, foshagite, sanbornite in float, you are in the right ground. Field specimens usually show a platy crystals habit, so train your eye for that shape before scanning the outcrop.
Common questions
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Find bigcreekite on the map
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