Zigrasite is an exceptionally rare magnesium-zirconium phosphate mineral found in highly evolved granite pegmatites. It typically occurs as small, clear tabular crystals and is highly prized by advanced micromount collectors due to its limited global occurrences.

Hardness

Mohs

Luster

Vitreous

Streak

White

Transparency

Transparent

mineralrare

Zigrasite

Hardness: 3
Luster: Vitreous
Streak: White
Transparency: Transparent

Is this zigrasite?

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

Often confused with

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

mineral

Morinite

Mohs 4.5

How to tell apart: Morinite is the harder of the two (Mohs 4.5 vs. 3).

How to tell apart: Roscherite is the harder of the two (Mohs 4.5 vs. 3).

Compare →

Often found alongside zigrasite

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

All properties

Chemical formula: MgZr(PO₄)₂·4H₂O
Mohs hardness: 3
Density: 2.8 g/cm³
Colors: White Colorless
Streak: White
Luster: Vitreous
Transparency: Transparent
Crystal system: Triclinic
Crystal habit: Tabular Crystals
Cleavage: Perfect
Rarity: Rare
Uses: Collector
Host rock: Granite Pegmatites
Typical price: $50-500 depending on specimen quality

Where rockhounds find zigrasite

Classic worldwide localities

Tip Top mine, South Dakota, USA

Field-hunting tip

Look in granite pegmatites country — that is the host setting where zigrasite typically forms. If you start seeing apatite, quartz, muscovite in float, you are in the right ground. Field specimens usually show a tabular crystals habit, so train your eye for that shape before scanning the outcrop.

Common questions

How do you identify zigrasite?+

Mohs hardness is 3. It typically shows a vitreous luster. The streak is white. Common colors include white, colorless.

Where is zigrasite found?+

Notable localities include Tip Top mine, South Dakota, USA.

How much is zigrasite worth?+

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

What rocks look like zigrasite?+

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

What minerals are found with zigrasite?+

Zigrasite commonly co-occurs with Apatite, Quartz, Muscovite, Beryl. Spotting any of these in float or country rock is a useful trip signal.

What kind of rock does zigrasite form in?+

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

What is zigrasite used for?+

Zigrasite is used in collector.

Find zigrasite on the map

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