Terrywallaceite is a rare silver-lead-antimony sulfosalt mineral found in hydrothermal vein deposits. It is primarily identified in lab settings via electron microprobe analysis, appearing as small, opaque metallic grains within associated sulfide assemblages.

Hardness

2.5

Mohs

Luster

Metallic

Streak

Black

Transparency

Opaque

mineralrareJalpaite Group family

Terrywallaceite

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

Is this terrywallaceite?

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

Often confused with

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

How to tell apart: Streak differs — Terrywallaceite leaves black, Freieslebenite leaves lead-gray.

Often found alongside terrywallaceite

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

All properties

Chemical formula: Ag₃PbSb₃S₇
Mohs hardness: 2.5
Density: 6.85 g/cm³
Colors: Black Gray
Streak: Black
Luster: Metallic
Transparency: Opaque
Crystal system: Monoclinic
Crystal habit: Anhedral Grains, Massive
Cleavage: None
Rarity: Rare
Uses: Collector
Host rock: Hydrothermal Veins
Typical price: $100-500+ per specimen

Where rockhounds find terrywallaceite

Classic worldwide localities

San Jose mine, Oruro, Bolivia

Field-hunting tip

Look in hydrothermal veins country — that is the host setting where terrywallaceite typically forms. If you start seeing pyrite, quartz, galena in float, you are in the right ground. Field specimens usually show a anhedral grains, massive habit, so train your eye for that shape before scanning the outcrop.

Common questions

How do you identify terrywallaceite?+

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

Where is terrywallaceite found?+

Notable localities include San Jose mine, Oruro, Bolivia.

How much is terrywallaceite worth?+

Typical asking prices fall in the range of $100-500+ per specimen. Quality, size, and provenance can move individual specimens well outside that range.

Is terrywallaceite safe to handle?+

It contains toxic constituents. Contains lead and silver; avoid ingestion, inhalation of dust, or prolonged skin contact, and wash hands thoroughly after handling. Handle with care, avoid grinding or breathing dust, and store separately.

What rocks look like terrywallaceite?+

Terrywallaceite is most often confused with Jalpaite, Freieslebenite, Diaphorite. A quick hardness test and a streak check separate the look-alikes faster than color alone.

What minerals are found with terrywallaceite?+

Terrywallaceite commonly co-occurs with Pyrite, Quartz, Galena, Siderite. Spotting any of these in float or country rock is a useful trip signal.

What kind of rock does terrywallaceite form in?+

Terrywallaceite typically forms in hydrothermal veins. Working float back to the host body is the standard way to chase a fresh occurrence.

What is terrywallaceite used for?+

Terrywallaceite is used in collector.

Find terrywallaceite on the map

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