Arkose is a sedimentary rock characterized by a high content of feldspar, typically exceeding 25 percent of its clastic components. It often forms from the rapid weathering and erosion of granitic terrain, leading to poorly sorted, angular grains in a matrix of quartz and clay. It is easily identified by its coarse, grainy texture and often pinkish or reddish coloration due to the high feldspar content.

Hardness

6-7

Mohs

Luster

Dull

Streak

White

Transparency

Opaque

sedimentarycommon

Arkose

Hardness: 6-7
Luster: Dull
Streak: White
Transparency: Opaque

Is this arkose?

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 arkose with a known reference. Arkose sits at Mohs 6-7 — softer than the next harder reference, harder than the previous one.
2
Check the streak
Drag the specimen across an unglazed porcelain plate. Arkose leaves a white streak.
3
Read the luster
Hold the specimen under a strong light. Arkose typically shows a dull luster.
4
Match the color range
Compare against the expected color range: pink, gray, tan, reddish.
5
Look at form & habit
Typical habit: clastic.

Often confused with

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

How to tell apart: Luster reads dull on Arkose and vitreous on Granite.

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Often found alongside arkose

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

All properties

Mohs hardness: 6-7
Density: 2.6-2.7 g/cm³
Colors: Pink Gray Tan Reddish
Streak: White
Luster: Dull
Transparency: Opaque
Crystal habit: Clastic
Cleavage: None
Rarity: Common
Uses: Construction, Ornamental
Host rock: Sedimentary Basin
Typical price: $1-20 per specimen

Where rockhounds find arkose

Classic worldwide localities

Scotland
USA (Colorado)
France
Germany

Field-hunting tip

Look in sedimentary basin country — that is the host setting where arkose typically forms. If you start seeing quartz, feldspar, mica in float, you are in the right ground. Field specimens usually show a clastic habit, so train your eye for that shape before scanning the outcrop.

Common questions

How do you identify arkose?+

Mohs hardness is 6-7. It typically shows a dull luster. The streak is white. Common colors include pink, gray, tan, reddish.

Where is arkose found?+

Notable localities include Scotland; USA (Colorado); France; Germany.

How much is arkose worth?+

Typical asking prices fall in the range of $1-20 per specimen. Quality, size, and provenance can move individual specimens well outside that range.

What rocks look like arkose?+

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

What minerals are found with arkose?+

Arkose commonly co-occurs with Quartz, Feldspar, Mica, Clay minerals. Spotting any of these in float or country rock is a useful trip signal.

What kind of rock does arkose form in?+

Arkose typically forms in sedimentary basin. Working float back to the host body is the standard way to chase a fresh occurrence.

What is arkose used for?+

Arkose is used in construction, ornamental.

Find arkose on the map

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