Ruarsite is a rare ruthenium-arsenic-sulfur mineral that typically occurs as microscopic inclusions within platinum-group ore deposits. Because it is rarely found in large visible crystals, collectors usually seek out polished ore sections or matrix samples containing associated platinum-group minerals.

Hardness

5-6

Mohs

Luster

Metallic

Streak

Black

Transparency

Opaque

mineralrare

Ruarsite

Hardness: 5-6
Luster: Metallic
Streak: Black
Transparency: Opaque

No image

Is this ruarsite?

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 ruarsite with a known reference. Ruarsite sits at Mohs 5-6 — softer than the next harder reference, harder than the previous one.
2
Check the streak
Drag the specimen across an unglazed porcelain plate. Ruarsite leaves a black streak.
3
Read the luster
Hold the specimen under a strong light. Ruarsite typically shows a metallic luster.
4
Match the color range
Compare against the expected color range: silver-white, gray.
5
Look at form & habit
Crystal system: monoclinic. Typical habit: anhedral grains, inclusions in other minerals.

Often confused with

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

How to tell apart: Laurite is the harder of the two (Mohs 7-7.5 vs. 5-6).

Often found alongside ruarsite

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

All properties

Chemical formula: RuAsS
Mohs hardness: 5-6
Density: 9.2-9.6 g/cm³
Colors: Silver-white Gray
Streak: Black
Luster: Metallic
Transparency: Opaque
Crystal system: Monoclinic
Crystal habit: Anhedral Grains, Inclusions in Other Minerals
Cleavage: None
Rarity: Rare
Uses: Collector
Host rock: Ultramafic Rocks, Platinum-group Mineral Deposits
Typical price: $50-300+ depending on size and association

Where rockhounds find ruarsite

Classic worldwide localities

Urals, Russia
Bushveld Complex, South Africa
Sudbury, Canada

Field-hunting tip

Look in ultramafic rocks, platinum-group mineral deposits country — that is the host setting where ruarsite typically forms. If you start seeing laurite, sperrylite, platinum-group minerals in float, you are in the right ground. Field specimens usually show a anhedral grains, inclusions in other minerals habit, so train your eye for that shape before scanning the outcrop.

Common questions

How do you identify ruarsite?+

Mohs hardness is 5-6. It typically shows a metallic luster. The streak is black. Common colors include silver-white, gray.

Where is ruarsite found?+

Notable localities include Urals, Russia; Bushveld Complex, South Africa; Sudbury, Canada.

How much is ruarsite worth?+

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

Is ruarsite safe to handle?+

It contains toxic constituents. Contains arsenic, which is toxic; handle with care and wash hands after contact to avoid ingestion or inhalation of dust. Handle with care, avoid grinding or breathing dust, and store separately.

What rocks look like ruarsite?+

Ruarsite is most often confused with Arsenopyrite, Laurite, Sperrylite. A quick hardness test and a streak check separate the look-alikes faster than color alone.

What minerals are found with ruarsite?+

Ruarsite commonly co-occurs with Laurite, Sperrylite, Platinum-group minerals, Chromite. Spotting any of these in float or country rock is a useful trip signal.

What kind of rock does ruarsite form in?+

Ruarsite typically forms in ultramafic rocks, platinum-group mineral deposits. Working float back to the host body is the standard way to chase a fresh occurrence.

What is ruarsite used for?+

Ruarsite is used in collector.

Find ruarsite on the map

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