Steacyite is a rare thorium-bearing silicate mineral found in alkaline pegmatites and igneous complexes. Collectors prize it primarily for its distinct crystal habits and its association with other rare minerals at localities like Mont Saint-Hilaire.

Hardness

Mohs

Luster

Vitreous

Streak

White

Transparency

Translucent

mineralrareSteacyite Group family

Steacyite

Hardness: 5
Luster: Vitreous
Streak: White
Transparency: Translucent

Is this steacyite?

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 steacyite with a known reference. Steacyite sits at Mohs 5 — softer than the next harder reference, harder than the previous one.
2
Check the streak
Drag the specimen across an unglazed porcelain plate. Steacyite leaves a white streak.
3
Read the luster
Hold the specimen under a strong light. Steacyite typically shows a vitreous luster.
4
Match the color range
Compare against the expected color range: yellow, brown, gray, colorless.
5
Look at form & habit
Crystal system: tetragonal. Typical habit: equant to tabular crystals.

Often confused with

Steacyite vs. its common look-alikes — and how to tell them apart in the field.

How to tell apart: Streak differs — Steacyite leaves white, Thorite leaves dark brown; luster reads vitreous on Steacyite and resinous on Thorite.

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Often found alongside steacyite

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

All properties

Chemical formula: KTh(Ca,Na)₂Si₈O₂₀
Mohs hardness: 5
Density: 2.53 g/cm³
Colors: Yellow Brown Gray Colorless
Streak: White
Luster: Vitreous
Transparency: Translucent
Crystal system: Tetragonal
Crystal habit: Equant to Tabular Crystals
Cleavage: Poor
Rarity: Rare
Uses: Collector
Host rock: Alkaline Igneous Rocks
Typical price: $20-150 per specimen depending on size and intensity of radioactivity

Where rockhounds find steacyite

Classic worldwide localities

Mont Saint-Hilaire, Quebec, Canada
Kola Peninsula, Russia
Ilimaussaq complex, Greenland

Field-hunting tip

Look in alkaline igneous rocks country — that is the host setting where steacyite typically forms. If you start seeing quartz, microcline, aegirine in float, you are in the right ground. Field specimens usually show a equant to tabular crystals habit, so train your eye for that shape before scanning the outcrop.

Common questions

How do you identify steacyite?+

Mohs hardness is 5. It typically shows a vitreous luster. The streak is white. Common colors include yellow, brown, gray, colorless.

Where is steacyite found?+

Notable localities include Mont Saint-Hilaire, Quebec, Canada; Kola Peninsula, Russia; Ilimaussaq complex, Greenland.

How much is steacyite worth?+

Typical asking prices fall in the range of $20-150 per specimen depending on size and intensity of radioactivity. Quality, size, and provenance can move individual specimens well outside that range.

Is steacyite safe to handle?+

This mineral is radioactive. Steacyite contains thorium and is radioactive; handle with care and store away from other sensitive materials in a ventilated area. Handle with care, avoid grinding or breathing dust, and store separately.

What rocks look like steacyite?+

Steacyite is most often confused with Ekanite, Thorite. A quick hardness test and a streak check separate the look-alikes faster than color alone.

What minerals are found with steacyite?+

Steacyite commonly co-occurs with Quartz, Microcline, Aegirine, Arfvedsonite. Spotting any of these in float or country rock is a useful trip signal.

What kind of rock does steacyite form in?+

Steacyite typically forms in alkaline igneous rocks. Working float back to the host body is the standard way to chase a fresh occurrence.

What is steacyite used for?+

Steacyite is used in collector.

Find steacyite on the map

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