Impactite is a rock formed by the transformation of terrestrial material during a meteorite impact. These rocks often contain shocked minerals like coesite or stishovite and can range from glassy, tektite-like shards to heavily brecciated rock formations found within impact craters.

Hardness

5-7

Mohs

Luster

Vitreous

Transparency

Translucent

sedimentaryuncommon

Impactite

Also: impact glass

Hardness: 5-7
Luster: Vitreous
Transparency: Translucent

Is this impactite?

4-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 impactite with a known reference. Impactite sits at Mohs 5-7, softer than the next harder reference, harder than the previous one.
2
Pick out the minerals
Composition: Shock-metamorphosed target rock, impact melt or a mix of the two, sometimes with meteorite fragments. Identify the two or three most abundant grains.
3
Read the luster
Hold the specimen under a strong light. Luster: vitreous.
4
Match the color range
Compare against the expected color range: black, brown, green, yellow, gray.

Often confused with

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

$Obsidian showing the bright conchoidal fracture and glassy black break that identify it$

How to tell apart: Luster reads vitreous on Impactite and glassy on Fulgurite.

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Often found alongside impactite

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

All properties

Mohs hardness: 5-7
Density: 2.3-2.6 g/cm³
Colors: Black Brown Green Yellow Gray
Luster: Vitreous
Transparency: Translucent
Rarity: Uncommon
Uses: Collector, Scientific study
Host rock: impact crater sites
Composition: Shock-metamorphosed target rock, impact melt or a mix of the two, sometimes with meteorite fragments

Where rockhounds find impactite

Classic worldwide localities

Nördlinger Ries, Germany
Henbury Crater, Australia
Meteor Crater, USA
Libyan Desert, Egypt
Indochina

Field-hunting tip

Where it forms: impact crater sites. If you start seeing coesite, stishovite, nickel-iron meteorites in float, you are in the right ground.

Common questions

How do you identify impactite?+

Mohs hardness is 5-7. Composition: Shock-metamorphosed target rock, impact melt or a mix of the two, sometimes with meteorite fragments. Luster: vitreous. Common colors include black, brown, green, yellow.

Where is impactite found?+

Notable localities include Nördlinger Ries, Germany; Henbury Crater, Australia; Meteor Crater, USA; Libyan Desert, Egypt; Indochina.

What rocks look like impactite?+

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

What minerals are found with impactite?+

Impactite commonly co-occurs with coesite, stishovite, nickel-iron meteorites. Spotting any of these in float or country rock is a useful trip signal.

What kind of rock does impactite form in?+

Where it forms: impact crater sites. Working float back to the host body is the standard way to chase a fresh occurrence.

What is impactite used for?+

Impactite is used in collector, scientific study.

Find impactite on the map

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