Jennite is a rare calcium silicate hydrate typically found in metamorphosed limestone deposits. It is best identified by its distinctive pink or white acicular, radiating spray habit and soft, pearly luster.
Is this jennite?
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 jennite with a known reference. Jennite sits at Mohs 2.5 — softer than the next harder reference, harder than the previous one.
- 2Check the streakDrag the specimen across an unglazed porcelain plate. Jennite leaves a white streak.
- 3Read the lusterHold the specimen under a strong light. Jennite typically shows a pearly luster.
- 4Match the color rangeCompare against the expected color range: white, pink, brownish.
- 5Look at form & habitCrystal system: triclinic. Typical habit: radiating fibrous or acicular sprays.
Often confused with
Jennite vs. its common look-alikes — and how to tell them apart in the field.
How to tell apart: Wollastonite is the harder of the two (Mohs 4.5-5 vs. 2.5); luster reads pearly on Jennite and vitreous on Wollastonite.
How to tell apart: Luster reads pearly on Jennite and vitreous on Afwillite.
Often found alongside jennite
Minerals reported to co-occur with jennite. Spotting these in float or country rock is a strong cue you are in the right ground.
All properties
- Chemical formula
- Ca₉Si₆O₁₈(OH)₆·8H₂O
- Mohs hardness
- 2.5
- Density
- 2.33 g/cm³
- Streak
- White
- Luster
- Pearly
- Transparency
- Translucent
- Crystal system
- Triclinic
- Crystal habit
- Radiating Fibrous or Acicular Sprays
- Cleavage
- Perfect in One Direction
- Rarity
- Rare
- Uses
- Collector
- Host rock
- Metamorphosed Limestone Contact Zones
- Typical price
- $20-200 thumbnail
Where rockhounds find jennite
Classic worldwide localities
- Crestmore Quarry, Riverside, California, USA
- Nea Michaniona, Greece
Field-hunting tip
Look in metamorphosed limestone contact zones country — that is the host setting where jennite typically forms. If you start seeing ettringite, riversideite, thomasite in float, you are in the right ground. Field specimens usually show a radiating fibrous or acicular sprays habit, so train your eye for that shape before scanning the outcrop.
Common questions
How do you identify jennite?+
Where is jennite found?+
How much is jennite worth?+
What rocks look like jennite?+
What minerals are found with jennite?+
What kind of rock does jennite form in?+
What is jennite used for?+
Find jennite on the map
RockHoundR shows mapped rockhounding spots, access rules, and lets you log every find.
