Kentbrooksite is a rare silicate mineral belonging to the eudialyte group, characterized by its distinctive brown coloration and trigonal crystal symmetry. It is primarily found in highly alkaline igneous rocks like those in the Mont Saint-Hilaire region. Collectors prize it as a rare member of the eudialyte family, often occurring as small inclusions or grains within complex pegmatitic matrices.
Is this kentbrooksite?
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 kentbrooksite with a known reference. Kentbrooksite 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. Kentbrooksite leaves a white streak.
- 3Read the lusterHold the specimen under a strong light. Kentbrooksite typically shows a vitreous luster.
- 4Match the color rangeCompare against the expected color range: brown, yellow-brown, pinkish-brown.
- 5Look at form & habitCrystal system: trigonal. Typical habit: equant to tabular crystals, often in subhedral grains.
Often confused with
Kentbrooksite vs. its common look-alikes — and how to tell them apart in the field.
Often found alongside kentbrooksite
Minerals reported to co-occur with kentbrooksite. Spotting these in float or country rock is a strong cue you are in the right ground.
All properties
- Chemical formula
- (Na,Ca,REE)₄(Zr,Ti)(Si₂O₇)(OH,F)₂
- Mohs hardness
- 5-6
- Density
- 2.98 g/cm³
- Streak
- White
- Luster
- Vitreous
- Transparency
- Translucent
- Crystal system
- Trigonal
- Crystal habit
- Equant to Tabular Crystals, Often in Subhedral Grains
- Cleavage
- None
- Rarity
- Rare
- Uses
- Collector
- Host rock
- Alkaline Igneous Complexes (syenites and Pegmatites)
- Typical price
- $50-300 per specimen depending on size and quality
Where rockhounds find kentbrooksite
Classic worldwide localities
- Mont Saint-Hilaire (Canada)
- Khibiny Massif (Russia)
Field-hunting tip
Look in alkaline igneous complexes (syenites and pegmatites) country — that is the host setting where kentbrooksite typically forms. If you start seeing aegirine, microcline, nepheline in float, you are in the right ground. Field specimens usually show a equant to tabular crystals, often in subhedral grains habit, so train your eye for that shape before scanning the outcrop.
Common questions
How do you identify kentbrooksite?+
Where is kentbrooksite found?+
How much is kentbrooksite worth?+
Is kentbrooksite safe to handle?+
What rocks look like kentbrooksite?+
What minerals are found with kentbrooksite?+
What kind of rock does kentbrooksite form in?+
What is kentbrooksite used for?+
Find kentbrooksite on the map
RockHoundR shows mapped rockhounding spots, access rules, and lets you log every find.
