Ophirite is a rare calcium magnesium arsenate mineral typically found as small, vibrant yellow platy crystals or crusts. It is primarily known from the Gold Hill district in Utah, where it forms in oxidized zones of arsenic-rich mineral deposits.

Hardness

Mohs

Luster

Vitreous

Streak

Yellow

Transparency

Transparent

mineralrarenull family

Ophirite

Hardness: 2
Luster: Vitreous
Streak: Yellow
Transparency: Transparent

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Is this ophirite?

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 ophirite with a known reference. Ophirite sits at Mohs 2 — softer than the next harder reference, harder than the previous one.
2
Check the streak
Drag the specimen across an unglazed porcelain plate. Ophirite leaves a yellow streak.
3
Read the luster
Hold the specimen under a strong light. Ophirite typically shows a vitreous luster.
4
Match the color range
Compare against the expected color range: yellow, yellowish-orange.
5
Look at form & habit
Crystal system: monoclinic. Typical habit: platy crystals, crusts.

Often confused with

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

mineral

Conichalcite

Mohs 4.5

How to tell apart: Conichalcite is the harder of the two (Mohs 4.5 vs. 2); streak differs — Ophirite leaves yellow, Conichalcite leaves light green.

How to tell apart: Austinite is the harder of the two (Mohs 4 vs. 2); streak differs — Ophirite leaves yellow, Austinite leaves white.

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Often found alongside ophirite

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

All properties

Chemical formula: Ca₂Mg₃(H₂O)₄(AsO₄)₂F₄
Mohs hardness: 2
Density: 4.26 g/cm³
Colors: Yellow Yellowish-orange
Streak: Yellow
Luster: Vitreous
Transparency: Transparent
Crystal system: Monoclinic
Crystal habit: Platy Crystals, Crusts
Cleavage: Perfect
Fluorescence: Bright Yellow Under UV
Rarity: Rare
Uses: Collector
Host rock: Oxidized Arsenic-rich Hydrothermal Deposits
Typical price: $50-300 per specimen

Where rockhounds find ophirite

Classic worldwide localities

Gold Hill Mine, Utah, USA

Field-hunting tip

Look in oxidized arsenic-rich hydrothermal deposits country — that is the host setting where ophirite typically forms. If you start seeing arsenopyrite, scorodite, quartz in float, you are in the right ground. Field specimens usually show a platy crystals, crusts habit, so train your eye for that shape before scanning the outcrop.

Common questions

How do you identify ophirite?+

Mohs hardness is 2. It typically shows a vitreous luster. The streak is yellow. Common colors include yellow, yellowish-orange.

Where is ophirite found?+

Notable localities include Gold Hill Mine, Utah, USA.

How much is ophirite 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 ophirite safe to handle?+

It contains toxic constituents. Contains arsenic, which is toxic. Handle with care, wash hands after touching, and avoid inhaling dust. Handle with care, avoid grinding or breathing dust, and store separately.

What rocks look like ophirite?+

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

What minerals are found with ophirite?+

Ophirite commonly co-occurs with Arsenopyrite, Scorodite, Quartz. Spotting any of these in float or country rock is a useful trip signal.

What kind of rock does ophirite form in?+

Ophirite typically forms in oxidized arsenic-rich hydrothermal deposits. Working float back to the host body is the standard way to chase a fresh occurrence.

What is ophirite used for?+

Ophirite is used in collector.

Find ophirite on the map

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