Necklace made of emerald rhinestones in a size gradient

Necklace of emerald rondels graduating from 2.5 to 6.5 mm, with natural signs of growth, partly with fractures, combined with parts of 18K and clasp of 14K yellow gold, partly set with small sapphires and rubies, L: 43 cm, late 20th century, all in all good condition.