Roxbyite is a rare copper sulfide mineral primarily identified through X-ray diffraction due to its visual similarity to chalcocite. It typically occurs as massive aggregates in copper-rich ore bodies, often found associated with other copper sulfide minerals in hydrothermal systems.

Hardness

2.5-3

Mohs

Luster

Metallic

Streak

Black

Transparency

Opaque

mineralrare

Roxbyite

Hardness: 2.5-3
Luster: Metallic
Streak: Black
Transparency: Opaque

Is this roxbyite?

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 roxbyite with a known reference. Roxbyite sits at Mohs 2.5-3 — softer than the next harder reference, harder than the previous one.
2
Check the streak
Drag the specimen across an unglazed porcelain plate. Roxbyite leaves a black streak.
3
Read the luster
Hold the specimen under a strong light. Roxbyite typically shows a metallic luster.
4
Match the color range
Compare against the expected color range: dark gray, black.
5
Look at form & habit
Crystal system: monoclinic. Typical habit: massive.

Often confused with

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

mineral

Chalcocite

Mohs 2.5-3

How to tell apart: Streak differs — Roxbyite leaves black, Chalcocite leaves lead-gray to black.

Often found alongside roxbyite

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

All properties

Chemical formula: Cu₁.₇₈S
Mohs hardness: 2.5-3
Density: 5.68 g/cm³
Colors: Dark Gray Black
Streak: Black
Luster: Metallic
Transparency: Opaque
Crystal system: Monoclinic
Crystal habit: Massive
Cleavage: None
Rarity: Rare
Uses: Collector
Host rock: Hydrothermal Copper Deposits
Typical price: $50-300 per specimen

Where rockhounds find roxbyite

Classic worldwide localities

Olympic Dam mine, South Australia
Leonard mine, Butte, Montana, USA

Field-hunting tip

Look in hydrothermal copper deposits country — that is the host setting where roxbyite typically forms. If you start seeing chalcocite, digenite, bornite in float, you are in the right ground. Field specimens usually show a massive habit, so train your eye for that shape before scanning the outcrop.

Common questions

How do you identify roxbyite?+

Mohs hardness is 2.5-3. It typically shows a metallic luster. The streak is black. Common colors include dark gray, black.

Where is roxbyite found?+

Notable localities include Olympic Dam mine, South Australia; Leonard mine, Butte, Montana, USA.

How much is roxbyite 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 roxbyite safe to handle?+

It contains toxic constituents. Contains copper and sulfur; wash hands after handling and avoid inhaling dust. Handle with care, avoid grinding or breathing dust, and store separately.

What rocks look like roxbyite?+

Roxbyite is most often confused with Chalcocite, Digenite, Anilite. A quick hardness test and a streak check separate the look-alikes faster than color alone.

What minerals are found with roxbyite?+

Roxbyite commonly co-occurs with Chalcocite, Digenite, Bornite, Chalcopyrite. Spotting any of these in float or country rock is a useful trip signal.

What kind of rock does roxbyite form in?+

Roxbyite typically forms in hydrothermal copper deposits. Working float back to the host body is the standard way to chase a fresh occurrence.

What is roxbyite used for?+

Roxbyite is used in collector.

Find roxbyite on the map

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