Tritomite-(Y) is a rare radioactive borosilicate mineral found primarily in alkaline syenite pegmatites. It usually occurs as massive, dull grains rather than well-formed crystals, often requiring professional testing to distinguish from other similar rare-earth minerals.

Hardness

5.5

Mohs

Luster

Vitreous

Streak

White

Transparency

Translucent

mineralrareTritomite Group family

Tritomite-(Y)

Hardness: 5.5
Luster: Vitreous
Streak: White
Transparency: Translucent

Is this tritomite-(y)?

5-step field check

Run through these checks against the specimen in your hand. The more boxes tick, the more confident the ID.

1
Test the hardness
Try to scratch tritomite-(y) with a known reference. Tritomite-(Y) sits at Mohs 5.5 — softer than the next harder reference, harder than the previous one.
2
Check the streak
Drag the specimen across an unglazed porcelain plate. Tritomite-(Y) leaves a white streak.
3
Read the luster
Hold the specimen under a strong light. Tritomite-(Y) typically shows a vitreous luster.
4
Match the color range
Compare against the expected color range: brown, dark brown, reddish brown.
5
Look at form & habit
Crystal system: trigonal. Typical habit: massive, anhedral grains.

Often confused with

Tritomite-(Y) vs. its common look-alikes — and how to tell them apart in the field.

How to tell apart: Luster reads vitreous on Tritomite-(Y) and resinous on Monazite.

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Often found alongside tritomite-(y)

Minerals reported to co-occur with tritomite-(y). Spotting these in float or country rock is a strong cue you are in the right ground.

All properties

Chemical formula: (Ce,La,Y,Th)₅(SiO₄,BO₄)₃(OH,F)
Mohs hardness: 5.5
Density: 4.15-4.43 g/cm³
Colors: Brown Dark Brown Reddish Brown
Streak: White
Luster: Vitreous
Transparency: Translucent
Crystal system: Trigonal
Crystal habit: Massive, Anhedral Grains
Cleavage: None
Rarity: Rare
Uses: Collector
Host rock: Syenite Pegmatites
Typical price: $50-300 per specimen

Where rockhounds find tritomite-(y)

Classic worldwide localities

Langesundsfjord, Norway
Kola Peninsula, Russia
Mont Saint-Hilaire, Canada

Field-hunting tip

Look in syenite pegmatites country — that is the host setting where tritomite-(y) typically forms. If you start seeing aegirine, microcline, nepheline in float, you are in the right ground. Field specimens usually show a massive, anhedral grains habit, so train your eye for that shape before scanning the outcrop.

Common questions

How do you identify tritomite-(y)?+

Mohs hardness is 5.5. It typically shows a vitreous luster. The streak is white. Common colors include brown, dark brown, reddish brown.

Where is tritomite-(y) found?+

Notable localities include Langesundsfjord, Norway; Kola Peninsula, Russia; Mont Saint-Hilaire, Canada.

How much is tritomite-(y) worth?+

Typical asking prices fall in the range of $50-300 per specimen. Quality, size, and provenance can move individual specimens well outside that range.

Is tritomite-(y) safe to handle?+

This mineral is radioactive. This mineral contains thorium and is radioactive; handle with care and store in a sealed container away from living areas. Handle with care, avoid grinding or breathing dust, and store separately.

What rocks look like tritomite-(y)?+

Tritomite-(Y) is most often confused with Apatite, Monazite. A quick hardness test and a streak check separate the look-alikes faster than color alone.

What minerals are found with tritomite-(y)?+

Tritomite-(Y) commonly co-occurs with Aegirine, Microcline, Nepheline, Eudialyte. Spotting any of these in float or country rock is a useful trip signal.

What kind of rock does tritomite-(y) form in?+

Tritomite-(Y) typically forms in syenite pegmatites. Working float back to the host body is the standard way to chase a fresh occurrence.

What is tritomite-(y) used for?+

Tritomite-(Y) is used in collector.

Find tritomite-(y) on the map

RockHoundR shows mapped rockhounding spots, access rules, and lets you log every find.