Steinmetzite is a rare phosphate mineral typically found as small, thin platy crystals in the oxidation zones of phosphate-rich granite pegmatites. It is often discovered as an alteration product of other phosphate minerals like phosphophyllite, and collectors should look for its distinctive triclinic bladed habit.

Hardness

3.5

Mohs

Luster

Vitreous

Streak

White

Transparency

Transparent

mineralrare

Steinmetzite

Hardness: 3.5
Luster: Vitreous
Streak: White
Transparency: Transparent

Is this steinmetzite?

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 steinmetzite with a known reference. Steinmetzite sits at Mohs 3.5, softer than the next harder reference, harder than the previous one.
2
Check the streak
Drag the specimen across an unglazed porcelain plate. Steinmetzite leaves a white streak.
3
Read the luster
Hold the specimen under a strong light. Steinmetzite typically shows a vitreous luster.
4
Match the color range
Compare against the expected color range: white, pale yellow.
5
Look at form & habit
Crystal system: triclinic. Typical habit: platy crystals.

Often confused with

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

Often found alongside steinmetzite

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

All properties

Chemical formula: Zn₂Fe(PO₄)₂(OH)₂·3H₂O
Mohs hardness: 3.5
Density: 2.81 g/cm³
Colors: White Pale Yellow
Streak: White
Luster: Vitreous
Transparency: Transparent
Crystal system: Triclinic
Crystal habit: Platy Crystals
Cleavage: Perfect
Rarity: Rare
Uses: Collector
Host rock: Granite Pegmatites
Typical price: $100-500+ per specimen

Where rockhounds find steinmetzite

Classic worldwide localities

Hagendorf-Sud Pegmatite, Bavaria, Germany
Tip Top Mine, South Dakota, USA

Field-hunting tip

Look in granite pegmatites country, the host setting where steinmetzite typically forms. If you start seeing phosphophyllite, triphylite, ludlamite in float, you are in the right ground. Field specimens usually show a platy crystals habit, so train your eye for that shape before scanning the outcrop.

Common questions

How do you identify steinmetzite?+

Mohs hardness is 3.5. It typically shows a vitreous luster. The streak is white. Common colors include white, pale yellow.

Where is steinmetzite found?+

Notable localities include Hagendorf-Sud Pegmatite, Bavaria, Germany; Tip Top Mine, South Dakota, USA.

How much is steinmetzite 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.

What rocks look like steinmetzite?+

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

What minerals are found with steinmetzite?+

Steinmetzite commonly co-occurs with Phosphophyllite, Triphylite, Ludlamite, Vivianite. Spotting any of these in float or country rock is a useful trip signal.

What kind of rock does steinmetzite form in?+

Steinmetzite typically forms in granite pegmatites. Working float back to the host body is the standard way to chase a fresh occurrence.

What is steinmetzite used for?+

Steinmetzite is used in collector.

Find steinmetzite on the map

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