Gillespite is a rare barium iron silicate known for its distinct, vibrant red color and tabular, micaceous crystal habit. It is primarily sought after by advanced collectors for its striking appearance and rarity, typically occurring in association with sanbornite in metamorphic complexes.
Is this gillespite?
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 gillespite with a known reference. Gillespite sits at Mohs 4 — softer than the next harder reference, harder than the previous one.
- 2Check the streakDrag the specimen across an unglazed porcelain plate. Gillespite leaves a white streak.
- 3Read the lusterHold the specimen under a strong light. Gillespite typically shows a vitreous luster.
- 4Match the color rangeCompare against the expected color range: red, bright red.
- 5Look at form & habitCrystal system: tetragonal. Typical habit: tabular crystals, micaceous plates.
Often confused with
Gillespite vs. its common look-alikes — and how to tell them apart in the field.
Often found alongside gillespite
Minerals reported to co-occur with gillespite. Spotting these in float or country rock is a strong cue you are in the right ground.
All properties
- Chemical formula
- BaFeSi₄O₁₀
- Mohs hardness
- 4
- Density
- 3.35 g/cm³
- Colors
- Streak
- White
- Luster
- Vitreous
- Transparency
- Translucent
- Crystal system
- Tetragonal
- Crystal habit
- Tabular Crystals, Micaceous Plates
- Cleavage
- Perfect Basal
- Rarity
- Rare
- Uses
- Collector, Research
- Host rock
- Metamorphic Sanbornite-bearing Rocks
- Typical price
- $50-300 for small specimens
Where rockhounds find gillespite
Classic worldwide localities
- Big Creek, Fresno County, California, USA
- Sakha Republic, Russia
Field-hunting tip
Look in metamorphic sanbornite-bearing rocks country — that is the host setting where gillespite typically forms. If you start seeing sanbornite, quartz, witherite in float, you are in the right ground. Field specimens usually show a tabular crystals, micaceous plates habit, so train your eye for that shape before scanning the outcrop.
Common questions
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Find gillespite on the map
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