Meionite is a calcium-rich member of the scapolite group, typically found in contact metamorphic rocks like skarns. Collectors often look for its distinct tetragonal prismatic habit and its characteristic bright fluorescence under ultraviolet light.
Is this meionite?
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 meionite with a known reference. Meionite sits at Mohs 5-6, 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 to pearly or resinous.
- 4Match the color rangeCompare against the expected color range: bluish, brownish, colorless, violet, greenish.
- 5Look at form & habitCrystal system: tetragonal. Typical habit: columnar, fibrous, massive.
Often confused with
Meionite vs. its common look-alikes, and how to tell them apart in the field.
Often found alongside meionite
Minerals reported to co-occur with meionite. Spotting these in float or country rock is a strong cue you are in the right ground.
All properties
- Chemical formula
- Ca₄Al₆Si₆O₂₄CO₃
- Mohs hardness
- 5-6
- Density
- 2.74-2.78 g/cm³
- Streak
- White
- Luster
- Vitreous to pearly or resinous
- Transparency
- Transparent to opaque
- Crystal system
- Tetragonal
- Crystal habit
- Columnar, fibrous, massive
- Cleavage
- {100}, {110}, distinct
- Fluorescence
- Yellow-white under SW UV; red under LW UV
- Rarity
- Uncommon
- Uses
- Collector, Research
- Host rock
- Typically in regionally metamorphosed rocks, especially marbles, calcareous gneisses, granulites, and greenschists
Where rockhounds find meionite
Classic worldwide localities
- Rossie, St. Lawrence Co., New York, USA
- Bolton, Worcester Co., Massachusetts, USA
- Cutcane Creek, Fannin Co., Georgia, USA
- Monte Somma and Vesuvius, Campania, Italy
- Laacher See, Eifel district, Germany
- Pargas and Pusunsaari, Finland
Field-hunting tip
Where it forms: Typically in regionally metamorphosed rocks, especially marbles, calcareous gneisses, granulites, and greenschists. If you start seeing plagioclase, garnet, pyroxenes in float, you are in the right ground. Typical habit: columnar, fibrous, massive. Train your eye for that shape before scanning the outcrop.
Common questions
How do you identify meionite?+
Where is meionite found?+
What rocks look like meionite?+
What minerals are found with meionite?+
What kind of rock does meionite form in?+
What is meionite used for?+
Find meionite on the map
RockHoundR shows mapped rockhounding spots, access rules, and lets you log every find.
