Ross-Simons - .20ct t. w. Diamond Star, Moon Necklace in 18kt Yellow Gold Over Silver. 20". This celestial necklace twinkles with .20 ct. t. w. diamonds set in polished 18kt yellow gold over sterling silver on a rope chain. You'll look out of this world in this stylish piece! Springring clasp, diamond star and moon necklace. Diamond birthstones are the perfect gift for April birthdays.