organic/biological specimen

Sea Bean (Hamburger Bean)

Mucuna sloanei

Hardness: 3-4 (durable seed coat); Color: dark brown to black with a prominent dark band (hilum); Luster: waxy or dull-shiny; Structure: rounded, flattened disk-like shape; Specific gravity: floats in seawater.

Hardness: 3-4 (durable seed coat)
Color: dark brown to black with a prominent dark band (hilum)
Luster: waxy or dull-shiny

Identified March 27, 2026More organic/biological specimen →

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Physical properties

Formation & geological history

These are tropical seeds from vines in the pea family (Fabaceae). They fall into rivers in Central or South America and drift thousands of miles via ocean currents (long-distance dispersal). They can remain viable in salt water for years.

Uses & applications

Used in traditional jewelry, beachcombing collections, and sometimes as lucky charms or "wishing beans." Historically, they were used as medicine in some cultures or ground into paste.

Geological facts

Also known as the 'Hamburger Bean' due to its appearance; the dark band around the edge represents the hilum where it was attached to the seed pod. They are famous examples of 'drift seeds' that can travel from the Caribbean to European shores.

Field identification & locations

Identify by the distinctive 'hamburger' layering look and its extreme buoyancy. Primarily found along high-tide lines on tropical and subtropical beaches (Florida, Gulf of Mexico) and occasionally on European coasts after storms.

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