Sterling Silver Divine Proportion Fibonacci Spiral Nautilus Celtic Charm Pendant This sterling silver pendant features the symmetry and concord of the divine proportion or "Golden Mean," a mathematic ratio found throughout nature. Made of 925 sterling silver. Nickel free. Embrace harmony and balance with this sterling silver divine proportion nautilus pendant. The charm measures 1.38 inches by 0.69 inches and weighs 7.5 grams This pendant would make an excellent gift for lover of mathematics or natural harmony.