Stöfflerite is a rare high-pressure polymorph of calcium-rich feldspar discovered in impact craters. It is typically found as small, microscopic inclusions within impact-melted rocks alongside other shock-metamorphosed minerals. Collectors rarely encounter this mineral as it is primarily significant in planetary science and petrology research.

Hardness

Mohs

Luster

Vitreous

Streak

White

Transparency

Transparent

mineralrarePlagioclase Feldspar Group family

Stöfflerite

Hardness: 6
Luster: Vitreous
Streak: White
Transparency: Transparent

No image

Is this stöfflerite?

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 stöfflerite with a known reference. Stöfflerite sits at Mohs 6 — softer than the next harder reference, harder than the previous one.
2
Check the streak
Drag the specimen across an unglazed porcelain plate. Stöfflerite leaves a white streak.
3
Read the luster
Hold the specimen under a strong light. Stöfflerite typically shows a vitreous luster.
4
Match the color range
Compare against the expected color range: colorless, white.
5
Look at form & habit
Crystal system: monoclinic. Typical habit: tabular crystals.

Often confused with

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

Often found alongside stöfflerite

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

All properties

Chemical formula: Ca₂Al₄Si₈O₂₄
Mohs hardness: 6
Density: 2.75 g/cm³
Colors: Colorless White
Streak: White
Luster: Vitreous
Transparency: Transparent
Crystal system: Monoclinic
Crystal habit: Tabular Crystals
Cleavage: Perfect
Rarity: Rare
Uses: Scientific Study, Collector
Host rock: Impact Melt Breccia
Typical price: n/a (extremely rare specimen, typically in institutional collections)

Where rockhounds find stöfflerite

Classic worldwide localities

Nördlinger Ries crater, Germany

Field-hunting tip

Look in impact melt breccia country — that is the host setting where stöfflerite typically forms. If you start seeing maskelynite, coesite, stishovite 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 stöfflerite?+

Mohs hardness is 6. It typically shows a vitreous luster. The streak is white. Common colors include colorless, white.

Where is stöfflerite found?+

Notable localities include Nördlinger Ries crater, Germany.

How much is stöfflerite worth?+

Typical asking prices fall in the range of n/a (extremely rare specimen, typically in institutional collections). Quality, size, and provenance can move individual specimens well outside that range.

What rocks look like stöfflerite?+

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

What minerals are found with stöfflerite?+

Stöfflerite commonly co-occurs with Maskelynite, Coesite, Stishovite. Spotting any of these in float or country rock is a useful trip signal.

What kind of rock does stöfflerite form in?+

Stöfflerite typically forms in impact melt breccia. Working float back to the host body is the standard way to chase a fresh occurrence.

What is stöfflerite used for?+

Stöfflerite is used in scientific study, collector.

Find stöfflerite on the map

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