Johnsenite-(Ce) is a rare cyclosilicate member of the eudialyte group typically found in highly alkaline intrusive complexes. Collectors primarily seek it as small, trigonal-tabular crystals associated with exotic silicate minerals in nepheline syenites and pegmatites.
Is this johnsenite-(ce)?
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 johnsenite-(ce) with a known reference. Johnsenite-(Ce) 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.
- 4Match the color rangeCompare against the expected color range: pale yellow, bright orange.
- 5Look at form & habitCrystal system: trigonal. Typical habit: skeletal.
Often confused with
Johnsenite-(Ce) vs. its common look-alikes, and how to tell them apart in the field.
Often found alongside johnsenite-(ce)
Minerals reported to co-occur with johnsenite-(ce). Spotting these in float or country rock is a strong cue you are in the right ground.
All properties
- Chemical formula
- Na₁₂Ce₃Ca₆Mn₃Zr₃WSi₂₅O₇₃(CO₃)(OH)₂
- Mohs hardness
- 5-6
- Density
- 3.24 g/cm³
- Colors
- Streak
- White
- Luster
- Vitreous
- Transparency
- Transparent to translucent
- Crystal system
- Trigonal
- Crystal habit
- Skeletal
- Cleavage
- None
- Rarity
- Rare
- Uses
- Collector
- Host rock
- In a cavity near the margin of a marble xenolith in an igneous breccia along the contact between porphyritic nepheline syenite and sodalite syenite in an alkaline igneous complex
Where rockhounds find johnsenite-(ce)
Classic worldwide localities
- Poudrette Quarry, Mont Saint-Hilaire, Rouville County, Quebec, Canada (type locality)
Field-hunting tip
Where it forms: In a cavity near the margin of a marble xenolith in an igneous breccia along the contact between porphyritic nepheline syenite and sodalite syenite in an alkaline igneous complex. If you start seeing albite, calcite, pectolite in float, you are in the right ground. Typical habit: skeletal. Train your eye for that shape before scanning the outcrop.
Common questions
How do you identify johnsenite-(ce)?+
Where is johnsenite-(ce) found?+
What rocks look like johnsenite-(ce)?+
What minerals are found with johnsenite-(ce)?+
What kind of rock does johnsenite-(ce) form in?+
What is johnsenite-(ce) used for?+
Find johnsenite-(ce) on the map
RockHoundR shows mapped rockhounding spots, access rules, and lets you log every find.
