[en] Minute concentrations of unfamiliar particles (X⁺ or X^-) with atomic weights M between 10² and 10⁶ (10¹¹ and 10¹⁵ eV) may be remnants of the Big Bang or may originate in recent events. The adduct of X^- with a Z-nucleus acts as a superheavy isotope of (Z - 1). It is shown that although their geochemical separation would be less obvious than that of fractionally charged species containing unsaturated quarks it should be possible to concentrate these exotic isotopes. Exceptional cases are the neutral adducts pX and ²DX, which may form tiny molecules with a second proton, or a polymer with a density M x 10¹⁰ g cm^-3 which could act as a low-temperature fusion catalyst and explain the excess heat irradiated by Jupiter. (U.K.)