A complex hydrated magnesium silicate mineral named for its resemblance to cuttlefish bone, alternately named meerschaum (sea foam). The ideal composition, Mg₈(H₂O)₄(OH)₄Si₁₂O₃₀, is modified by some additional water of hydration, but is otherwise quite representative. The ideal density, 2.26 g/cm³ (1.31 oz/in.³), is never realized in aggregates. Interlaced disoriented fibers aggregate into a massive stone so porous that it floats on water. These stones are easily carved, take a high polish with wax, and harden when warmed. They have been valued from antiquity in the eastern Mediterranean region for ornaments and make attractive smoking pipes.