Iodargyrite is a rare silver halide mineral that forms in the oxidized zones of silver deposits. It typically appears as thin, yellowish, waxy-looking tabular crystals or coatings on other minerals and is highly prized by collectors for its role as a primary silver mineral.

Hardness

1.5

Mohs

Luster

Resinous

Streak

Yellow

Transparency

Translucent

mineralrare

Iodargyrite

Also: Iodyrite

Hardness: 1.5
Luster: Resinous
Streak: Yellow
Transparency: Translucent

Is this iodargyrite?

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 iodargyrite with a known reference. Iodargyrite sits at Mohs 1.5, softer than the next harder reference, harder than the previous one.
2
Check the streak
Drag the specimen across an unglazed porcelain plate. Iodargyrite leaves a yellow streak.
3
Read the luster
Hold the specimen under a strong light. Iodargyrite typically shows a resinous luster.
4
Match the color range
Compare against the expected color range: yellow, yellowish-green, brownish, colorless.
5
Look at form & habit
Crystal system: hexagonal. Typical habit: tabular crystals, massive, crusts.

Often confused with

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

mineral

Chlorargyrite

Mohs 1.5-2.5

How to tell apart: Streak differs, so Iodargyrite leaves yellow, Chlorargyrite leaves white.

How to tell apart: Streak differs, so Iodargyrite leaves yellow, Bromargyrite leaves yellowish-white.

Compare →

Often found alongside iodargyrite

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

All properties

Chemical formula: AgI
Mohs hardness: 1.5
Density: 5.6-5.7 g/cm³
Colors: Yellow Yellowish-green Brownish Colorless
Streak: Yellow
Luster: Resinous
Transparency: Translucent
Crystal system: Hexagonal
Crystal habit: Tabular Crystals, Massive, Crusts
Cleavage: Perfect Basal
Rarity: Rare
Uses: Collector, Scientific Research
Host rock: Oxidized Zones of Silver Ore Deposits
Typical price: $50-500 depending on crystal size and provenance

Where rockhounds find iodargyrite

Classic worldwide localities

Broken Hill, Australia
Tonopah, Nevada, USA
Cerro Gordo, California, USA
Chañarcillo, Chile
Aspen, Colorado, USA

Field-hunting tip

Look in oxidized zones of silver ore deposits country, the host setting where iodargyrite typically forms. If you start seeing chlorargyrite, silver, cerussite in float, you are in the right ground. Field specimens usually show a tabular crystals, massive, crusts habit, so train your eye for that shape before scanning the outcrop.

Common questions

How do you identify iodargyrite?+

Mohs hardness is 1.5. It typically shows a resinous luster. The streak is yellow. Common colors include yellow, yellowish-green, brownish, colorless.

Where is iodargyrite found?+

Notable localities include Broken Hill, Australia; Tonopah, Nevada, USA; Cerro Gordo, California, USA; Chañarcillo, Chile; Aspen, Colorado, USA.

How much is iodargyrite worth?+

Typical asking prices fall in the range of $50-500 depending on crystal size and provenance. Quality, size, and provenance can move individual specimens well outside that range.

Is iodargyrite safe to handle?+

It contains toxic constituents. Contains silver and iodine; avoid inhalation of dust and wash hands thoroughly after handling as it is sensitive to light and can degrade over time. Handle with care, avoid grinding or breathing dust, and store separately.

What rocks look like iodargyrite?+

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

What minerals are found with iodargyrite?+

Iodargyrite commonly co-occurs with Chlorargyrite, Silver, Cerussite, Galena, Smithsonite. Spotting any of these in float or country rock is a useful trip signal.

What kind of rock does iodargyrite form in?+

Iodargyrite typically forms in oxidized zones of silver ore deposits. Working float back to the host body is the standard way to chase a fresh occurrence.

What is iodargyrite used for?+

Iodargyrite is used in collector, scientific research.

Find iodargyrite on the map

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