It is a water insoluble low or high density polyethylene (PE-LD/ PE-HD). Rocks are mostly black-charcoal-grey coloured with occasional hues of green, blue, pink or yellow. Possesses medium strength, very high impact strength, good toughness, hardness, rigidity, high tensile strength and stiffness. Provides excellent ductility, good dimensional stability, excellent high and low temperature performance. Exhibits outstanding formability, good creep and chemical resistance. Used for packaging applications such as bottles, bags and pouches, clarity film, film wrap, food packaging film, agricultural film, heavy duty packaging, shrink film, specialty film, stretch hood, surface protection film and textile packaging film.

Single objects occasionally exhibit explicit traces of their base material which allow to draw conclusions about the original plastic product. For instance, some synthetic stones still feature typographical signs and logos that are identical with those usually found in the design of packaging foils and plastic bags. Thus, these remaining traces underline the general character of pyroplastic as a transformative element which slowly transitions from the sphere of human culture into an object of the so-called second nature.

The increasing circulation and erosion of pyroplastic in the ocean not only impacts the material composition of beaches. But by doing so, it also will affect the beaches future colour characteristics. Based on a large number of collected synthetic stones and the specific colour shades they frequently exhibit, a first speculative colour index was developed to explore this transformation. This index particularly reflects the potential colour spectrum of future beaches along the Bay of Biscay.