Quartzite (likely)

Pale gray to cream, granular and massive, with rusty-brown iron-oxide staining and possible relict bedding. Quartz has Mohs hardness 7, vitreous to dull luster, and no cleavage; the photo alone cannot confirm grain boundaries or hardness.

Forms when quartz-rich sandstone is recrystallized and fused during metamorphism, typically under heat and pressure. Its age and formation setting cannot be determined from the image.

Used as crushed aggregate, road stone, building and decorative stone; attractive pieces may be collected, though this specimen appears ordinary.

Quartzite is typically harder and more resistant to weathering than its sandstone precursor. A useful test is that it scratches glass and usually breaks across—not around—individual grains.

The specimen’s pale, quartz-rich appearance and faint layered markings fit quartzite or strongly metamorphosed sandstone; the user’s suggestion is consistent. Check a fresh break under magnification: interlocking grains and fracture through grains favor quartzite, while distinct grains that separate favor sandstone.