sedimentary

Wishing Stone (Graywacke with Quartz Vein)

Graywacke Sandstone containing a Quartz (SiO2) intrusion

AI-generated identification · may be incorrect

Hardness: 6.5-7 (Mohs scale); Color: Dark gray/greenish base with a white or cream stripe; Luster: Dull/earthy (matrix), vitreous (vein); Texture: Fine-grained clastic; Cleavage: None.

Hardness: 6
Color: Dark gray/greenish base with a white or cream stripe
Luster: Dull/earthy (matrix), vitreous (vein)

Identified June 30, 2026More sedimentary →

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Physical properties

Hardness: 6.5-7 (Mohs scale); Color: Dark gray/greenish base with a white or cream stripe; Luster: Dull/earthy (matrix), vitreous (vein); Texture: Fine-grained clastic; Cleavage: None.

Formation & geological history

Formed from the rapid deposition of muddy sand in deep ocean environments (turbidites). The white line is a hydrothermal vein formed when mineral-rich water filled a crack in the rock and crystallized over millions of years.

Uses & applications

Commonly used as a decorative pocket stone or garden rock; historically used in construction and road base due to its extreme hardness and durability.

Geological facts

In folklore, these are called 'Wishing Stones.' To make a wish, you must find one with a single continuous white line that circles the entire rock without breaking.

Field identification & locations

Identify by looking for a smooth, water-worn cobble with a distinct, single white stripe. Most commonly found on beaches or in riverbeds where glacial or water erosion has polished the surface.