Marialite is the sodium-rich endmember of the scapolite group and typically forms in contact metamorphic environments. Collectors should look for its characteristic tetragonal prismatic crystals and strong orange fluorescence under ultraviolet light.
Is this marialite?
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 marialite with a known reference. Marialite sits at Mohs 5.5-6, 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, pearly, resinous.
- 4Match the color rangeCompare against the expected color range: colorless, bluish, brownish, violet, greenish.
- 5Look at form & habitCrystal system: tetragonal. Typical habit: prismatic crystals with pyramidal terminations, often elongated.
Often confused with
Marialite vs. its common look-alikes, and how to tell them apart in the field.
How to tell apart: Quartz is the harder of the two (Mohs 7 vs. 5.5-6).
How to tell apart: Marialite is noticeably harder (Mohs 5.5-6 vs. 3).
How to tell apart: Danburite is the harder of the two (Mohs 7-7.25 vs. 5.5-6).
Often found alongside marialite
Minerals reported to co-occur with marialite. Spotting these in float or country rock is a strong cue you are in the right ground.
All properties
- Chemical formula
- Na₄Al₃Si₉O₂₄Cl
- Mohs hardness
- 5.5-6
- Density
- 2.50-2.62 g/cm³
- Streak
- White
- Luster
- Vitreous, pearly, resinous
- Transparency
- Transparent to opaque
- Crystal system
- Tetragonal
- Crystal habit
- Prismatic crystals with pyramidal terminations, often elongated
- Cleavage
- {100}, {110}, distinct
- Fluorescence
- Strong yellow under LW UV
- Rarity
- Uncommon
- Uses
- Collector, Gemstone
- Host rock
- Typically in regionally metamorphosed rocks, especially marbles, calcareous gneisses, granulites, and greenschists
Where rockhounds find marialite
Classic worldwide localities
- Hamburg and Franklin, Sussex Co., New Jersey, USA
- Natural Bridge, Jefferson Co., Macomb, St. Lawrence Co., and Olmsteadville, Essex Co., New York, USA
- French Creek, Chester Co., Pennsylvania, USA
- Pianura, west of Naples, Campania, Italy
- Slyudyanka region, near Lake Baikal, Siberia, Russia
- Bear Lake, Pontiac Co., Quebec, and Bancroft, Ontario, Canada
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: prismatic crystals with pyramidal terminations, often elongated. Train your eye for that shape before scanning the outcrop.
Common questions
How do you identify marialite?+
Where is marialite found?+
What rocks look like marialite?+
What minerals are found with marialite?+
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What is marialite used for?+
Find marialite on the map
RockHoundR shows mapped rockhounding spots, access rules, and lets you log every find.
