Sedimentary or Igneous

Painted River Pebble (likely Basalt or Greywacke)

Aphanitic Lithic Clast with Anthropogenic Pigment coating

Hardness: 6-7 (Mohs scale); Color: Naturally grey to brownish-grey with artificial neon pink acrylic/spray paint; Luster: Dull/Earthy; Structure: Fine-grained, rounded by fluvial erosion (water wear).

Hardness: 6-7 (Mohs scale)
Luster: Dull/Earthy

Identified March 29, 2026More sedimentary or igneous →

Identify your own rocks.

Get a report just like this from any photo, free.

App Store Google Play

Physical properties

Formation & geological history

Formed through volcanic cooling (if basalt) or sediment lithification (if greywacke) millions of years ago, then mechanically weathered and rounded in a high-energy river or coastal environment. The pink coating is modern human intervention.

Uses & applications

In this state, it is used as a decorative 'kindness rock,' a trail marker, or a game piece (like 'rock hiding'). Industrially, such stones are used for gravel, landscaping, or concrete aggregate.

Geological facts

This specimen is a 'geofact'—a natural stone modified by humans. The vibrant pink color is not a naturally occurring mineral vein but likely neon marking paint or acrylic used in communal 'rock hunting' hobbies.

Field identification & locations

Identify by looking for brush strokes, overspray, or peeling layers on a standard rounded river stone. These are found globally in riverbeds and beaches; the painted versions are common in suburban parks and hiking trails.

Other sedimentary or igneous specimens

See all

Pebble (likely a type of sandstone or quartzite pebble)

Clastic Sediment (specifically, a rudite-sized clast). If the pebble is composed of a specific rock type, its scientific name would be that rock type (e.g., 'Quartzite pebble', 'Granite pebble', 'Chert pebble'). Given its appearance, it is likely a metamorphic quartzite pebble or a hard sandstone pebble.

Sedimentary rock

Quartz Vein in Host Rock

Silicon Dioxide (SiO2) within Sedimentary or Igneous Matrix

igneous

Fluorite with Quartz coating

Calcium Fluoride (CaF2) with Silicon Dioxide (SiO2)

mineral

Opal

Hydrated Silica (SiO2·nH2O)

mineral

Healer's Gold (Pyrite and Magnetite in Schist)

Magnetite (Fe3O4) and Pyrite (FeS2) in Mica Schist

metamorphic

Red Garnet (likely Almandine or Pyrope)

Garnet group: X3Y2(SiO4)3 (e.g., Almandine: Fe3Al2Si3O12)

mineral