What are you actually holding?

Geology / Identification

Quartz is silicon dioxide, one of the most common minerals on earth. Quartzite is a hard metamorphic rock made largely of fused quartz grains. Both survive long journeys in surf, which is why bright white stones are among the most common finds on a New Jersey beach.

• Glassy to sugary surface, often milky white or clear
• Very hard — resists scratching from a steel blade
• Conchoidal (shell-like) chips on broken edges in pure quartz
• Quartzite shows a granular sparkle in direct sun

Geology / Identification

A metamorphic rock formed from limestone. On developed shorelines, tumbled marble often arrives from construction and seawall material rather than natural outcrops, then rounds beautifully in the surf.

• Soft enough to scratch with a steel point
• Sugary crystalline texture, frequently veined
• Warm white to grey, sometimes faintly translucent at edges

Geology / Identification

Dense microcrystalline silica rocks. Chert and flint break with sharp, curved fracture faces, which is why they were worked into tools for thousands of years.

• Waxy or dull luster rather than glassy
• Colors from tan and grey to near-black
• Sharp curved chips; edges stay keen after tumbling

Geology / Identification

An opaque variety of chalcedony colored by iron and other impurities. Jasper is tough and takes a natural polish in moving water.

• Opaque with an even, waxy finish
• Deep reds, browns, mustards, sometimes banded or spotted
• No visible crystals to the naked eye

Geology / Identification

Banded chalcedony formed as silica-rich fluids fill cavities in volcanic or sedimentary rock. Beach agates are prized for the way light passes through their edges.

• Translucent edges when held against the sun
• Concentric banding or cloudy internal structure
• Hard, glassy, and slightly greasy to the touch when wet

Geology / Identification

A fine-grained volcanic rock, dark and dense. Basalt cobbles round quickly and evenly in surf, producing the smooth black stones we find most often at dusk.

• Dark grey to black, uniformly fine-grained
• Heavy for its size
• Sometimes speckled with tiny gas bubbles (vesicles)

Geology / Identification

Volcanic glass formed when lava cools too quickly to crystallize. Genuine beach obsidian is uncommon on the Atlantic coast; dark glassy finds are more often man-made slag or sea glass.

• Deep glassy black with a mirror-like sheen
• Sharp conchoidal fracture
• Lighter than it looks compared with basalt

Geology / Identification

A group of green metamorphic minerals formed from altered ocean-floor rock. Serpentine often shows a slippery, soapy feel.

• Green to olive, sometimes mottled like snakeskin
• Soft — can be scratched with a knife point
• Smooth, almost waxy surface

Geology / Identification

A calcium-aluminum-iron silicate that grows in metamorphic rock, often as bright green streaks and veins inside a darker host stone.

• Distinct pistachio or yellow-green color
• Usually appears as veins or patches rather than whole pebbles
• Glassy luster on fresh faces

Geology / Identification

Nephrite is an extremely tough interlocking amphibole rock. True beach nephrite is rare on the East Coast; most green beach stones are serpentine or altered basalt.

• Exceptionally tough — resists chipping
• Deep green, sometimes with a soft internal glow when wet
• Slightly greasy luster when polished

Geology / Identification

A translucent orange to red-brown chalcedony colored by iron oxide. Carnelian glows warmly when backlit by low sun.

• Warm orange to rust red
• Translucent at the edges
• Smooth, waxy surface with no visible grains