Fresnoite is a rare barium titanium silicate mineral most famously found in the Sanbornite-bearing metamorphic rocks of California. It typically appears as small, lustrous yellow-orange crystals that exhibit a diagnostic bright yellow-green fluorescence under short-wave ultraviolet light.
Is this fresnoite?
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 fresnoite with a known reference. Fresnoite 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. Fresnoite leaves a white streak.
- 3Read the lusterHold the specimen under a strong light. Fresnoite typically shows a vitreous luster.
- 4Match the color rangeCompare against the expected color range: yellow, yellow-orange, colorless.
- 5Look at form & habitCrystal system: tetragonal. Typical habit: prismatic, tabular, or granular.
Often confused with
Fresnoite vs. its common look-alikes — and how to tell them apart in the field.
Often found alongside fresnoite
Minerals reported to co-occur with fresnoite. Spotting these in float or country rock is a strong cue you are in the right ground.
All properties
- Chemical formula
- Ba₂TiSi₂O₈
- Mohs hardness
- 3
- Density
- 4.05 g/cm³
- Streak
- White
- Luster
- Vitreous
- Transparency
- Transparent
- Crystal system
- Tetragonal
- Crystal habit
- Prismatic, Tabular, Or Granular
- Cleavage
- Distinct
- Fluorescence
- Bright Yellow-green Under SW UV
- Rarity
- Rare
- Uses
- Collector, Scientific Research
- Host rock
- Metamorphosed Limestone Inclusions in Sanbornite-bearing Rocks
- Typical price
- $50-500 thumbnail, $300-2000 cabinet
Where rockhounds find fresnoite
Classic worldwide localities
- Big Creek-Rush Creek area, California, USA
- Khibiny Massif, Russia
- Kola Peninsula, Russia
Field-hunting tip
Look in metamorphosed limestone inclusions in sanbornite-bearing rocks country — that is the host setting where fresnoite typically forms. If you start seeing benitoite, neptunite, sanbornite in float, you are in the right ground. Field specimens usually show a prismatic, tabular, or granular habit, so train your eye for that shape before scanning the outcrop.
Common questions
How do you identify fresnoite?+
Where is fresnoite found?+
How much is fresnoite worth?+
What rocks look like fresnoite?+
What minerals are found with fresnoite?+
What kind of rock does fresnoite form in?+
What is fresnoite used for?+
Find fresnoite on the map
RockHoundR shows mapped rockhounding spots, access rules, and lets you log every find.
