Vuagnatite is a rare calcium aluminum silicate typically found as small, white prismatic crystals. It is almost exclusively found in rodingites associated with ophiolitic rocks and is highly sought after by systematic mineral collectors. It is visually similar to prehnite but can be distinguished through analytical testing or distinct crystal habits.
Is this vuagnatite?
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 vuagnatite with a known reference. Vuagnatite sits at Mohs 6, 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: vitreous.
- 4Match the color rangeCompare against the expected color range: white, colorless, light pink.
- 5Look at form & habitCrystal system: orthorhombic. Typical habit: prismatic to acicular crystals, often as radial aggregates or massive.
Often confused with
Vuagnatite vs. its common look-alikes, and how to tell them apart in the field.
Often found alongside vuagnatite
Minerals reported to co-occur with vuagnatite. Spotting these in float or country rock is a strong cue you are in the right ground.
All properties
- Chemical formula
- CaAlSiO₄(OH)
- Mohs hardness
- 6
- Density
- 3.42 g/cm³
- Colors
- Streak
- White
- Luster
- Vitreous
- Transparency
- Semitransparent
- Crystal system
- Orthorhombic
- Crystal habit
- Prismatic to acicular crystals, often as radial aggregates or massive
- Cleavage
- Perfect
- Rarity
- Rare
- Uses
- Collector, Lapidary
- Host rock
- In rodingitized dikes of pegmatitic anorthositic gabbro crosscutting harzburgite-serpentines in an ophiolite (Taurus Mountains, Turkey)
Where rockhounds find vuagnatite
Classic worldwide localities
- Red Mountain, Mendocino Co., California, USA
- Böģürtlen Tepe Hill, 10 km northeast of Doģanbaba, Taurus Mountains, Burdur Province, Turkey
- Livingstone Mountains, Southland, New Zealand
- Shiraki, Toba, Mie Prefecture, Japan
- Wessels mine, near Kuruman, Cape Province, South Africa
Field-hunting tip
Where it forms: In rodingitized dikes of pegmatitic anorthositic gabbro crosscutting harzburgite-serpentines in an ophiolite (Taurus Mountains, Turkey). If you start seeing chantalite, prehnite, hydrogrossular in float, you are in the right ground. Typical habit: prismatic to acicular crystals, often as radial aggregates or massive. Train your eye for that shape before scanning the outcrop.
Common questions
How do you identify vuagnatite?+
Where is vuagnatite found?+
What rocks look like vuagnatite?+
What minerals are found with vuagnatite?+
What kind of rock does vuagnatite form in?+
What is vuagnatite used for?+
Find vuagnatite on the map
RockHoundR shows mapped rockhounding spots, access rules, and lets you log every find.
