Calciocatapleiite is a rare calcium-dominant member of the catapleiite group often found in alkaline igneous complexes. It typically occurs as small, tabular, platy crystals, and its identification usually requires sophisticated chemical analysis to distinguish it from the sodium-dominant catapleiite. Collectors prize it primarily for its occurrence in world-class alkaline pegmatites like Mont Saint-Hilaire.
Is this calciocatapleiite?
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 calciocatapleiite with a known reference. Calciocatapleiite sits at Mohs 4.5-5, 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 dull.
- 4Match the color rangeCompare against the expected color range: light yellow, reddish brown, cream.
- 5Look at form & habitCrystal system: orthorhombic. Typical habit: platy crystals, tabular.
Often confused with
Calciocatapleiite vs. its common look-alikes, and how to tell them apart in the field.
How to tell apart: Luster reads vitreous to dull on Calciocatapleiite and weakly vitreous or dull on Catapleiite.
How to tell apart: Wadeite is the harder of the two (Mohs 6-6.5 vs. 4.5-5); luster reads vitreous to dull on Calciocatapleiite and adamantine on Wadeite.
Often found alongside calciocatapleiite
Minerals reported to co-occur with calciocatapleiite. Spotting these in float or country rock is a strong cue you are in the right ground.
All properties
- Chemical formula
- CaZrSi₃O₉·H₂O
- Mohs hardness
- 4.5-5
- Density
- 2.77 g/cm³
- Streak
- White
- Luster
- Vitreous to dull
- Transparency
- Opaque, translucent on thin edges
- Crystal system
- Orthorhombic
- Crystal habit
- Platy crystals, tabular
- Cleavage
- Present
- Rarity
- Rare
- Uses
- Collector
- Host rock
- In cavities between crystals of microcline, in syenite pegmatites of a differentiated alkalic massif
Where rockhounds find calciocatapleiite
Classic worldwide localities
- Golden Horn batholith, Okanogan County, Washington, USA
- Burpala massif, about 120 km north of Lake Baikal, eastern Siberia, and from the Afrikanda complex, Kola Peninsula, Russia
- Strange Lake, Quebec-Labrador and Ice River, British Columbia, Canada
- Norra Kärr complex, Småland, Sweden
- Cnoc Rhaonastil, Isle of Islay, Scotland, UK
Field-hunting tip
Where it forms: In cavities between crystals of microcline, in syenite pegmatites of a differentiated alkalic massif. If you start seeing pyrophanite, pyrochlore, titanian låvenite in float, you are in the right ground. Typical habit: platy crystals, tabular. Train your eye for that shape before scanning the outcrop.
Common questions
How do you identify calciocatapleiite?+
Where is calciocatapleiite found?+
What rocks look like calciocatapleiite?+
What minerals are found with calciocatapleiite?+
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Find calciocatapleiite on the map
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