Ole Lynggaard,
The lock's diameter is approx. 10.4 mm, weight approx. 2.8 grams, the cultured pearls' diameter is approx. 6.9 mm, length excluding the lock is approx. 48.5 cm, detachable pendant in 18K white gold with a cultured pearl and a round brilliant-cut diamond approx. 0.07 ct, measures approx. 10.5x9.4x17.6 mm.
Cultured pearls' mother-of-pearl with some wear. Necklace and pendant likely not Ole Lynggaard.