Synthetic material (Not a rock or mineral)

Bouncy Ball (Synthetic Rubber Polymer)

Polybutadiene / Ethylene Vinyl Acetate (EVA)

AI-generated identification · may be incorrect

Hardness: Soft/Relatively pliable (1.5-2 on Mohs scale equivalent), Color: Translucent frosted exterior with internal neon green, yellow, and blue blobs, Luster: Dull/Waxy (exterior) to Vitreous (internal), Crystal Structure: Amorphous (non-crystalline polymer), Cleavage: None (elastic deformation), Specific Gravity: ~…

Hardness: Soft/Relatively pliable (1

Identified March 20, 2026More synthetic material (not a rock or mineral) →

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Physical properties

Formation & geological history

Formed via industrial injection molding or casting of liquid synthetic polymers. This is a man-made object created in a factory through polymerization and cross-linking of elastomer chains.

Uses & applications

Used as a toy for recreation, physical therapy, or stress relief. Its primary characteristic is high elasticity and energy return (bounciness).

Geological facts

Invented in 1965 by chemist Norman Stingley. Modern versions often use a mixture of polymer plastics and rubber to achieve specific bounciness and optical clarity. Unlike minerals, it will melt or char when exposed to high heat.

Field identification & locations

Identification includes checking for a 'mold seam' line, high elasticity (it will bounce when dropped), a rubbery smell when rubbed, and a lack of cold-to-the-touch feel associated with minerals like quartz. It contains internal colored dye droplets trapped during cooling.