Pewter Celtic Cross Symbol Pendant On Adjustable Black Cord Necklace. STYLE A Pewter Celtic cross symbol pendant on adjustable black cord necklace. The black cord necklace is fully adjustable from 42 - 82 cm (16 - 32 inches), so can be worn as long or as short as you like. The pendant is made of fine pewter, is nickel free and measures approximately 2.5 cm in diameter. The pendant is made of fine pewter, is nickel free and measures approximately 3cm in diameter. Other styles available.