Anticrystalline / Synthetic Alloy

Man-made Blank Ammunition (Brass)

CuZn (Cartridge Brass - roughly 70% Copper, 30% Zinc)

Hardness: 3-4 (Mohs); Color: Pale golden to brownish-yellow patina; Luster: Metallic; Structure: Face-centered cubic; Highly ductile and non-magnetic.

Hardness: 3-4 (Mohs)
Color: Pale golden to brownish-yellow patina
Luster: Metallic

Identified March 22, 2026More anticrystalline / synthetic alloy →

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Physical properties

Hardness: 3-4 (Mohs); Color: Pale golden to brownish-yellow patina; Luster: Metallic; Structure: Face-centered cubic; Highly ductile and non-magnetic.

Formation & geological history

Industrial manufacturing process. Brass is an alloy produced by melting copper and zinc together. This specific shape is achieved through deep drawing and cold forming for use in firearms.

Uses & applications

Used for training, cinematic special effects, or signaling. It contains propellant but lacks a projectile (bullet), instead featuring a crimped 'star' tip to hold the powder in place.

Geological facts

This is not a geological rock but a piece of modern cartridges. The crimped end indicates it is a 'blank'. If the primer at the base is indented, it has been fired; if not, it may still contain active propellant and should be handled with caution.

Field identification & locations

Identify by its metallic composition, perfectly cylindrical body with a rim or groove at the base, and a crimped nose. Commonly found at firing ranges or historical reenactment sites.

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