Hello! Would like some help valuing what I think is lavender chalcedony necklace with a 14K clasp

I would love to get help making sure the stone beads are, in fact, faceted lavender chalcedony. Also, the value of the necklace with its 14K white and yellow gold clasp. Beads go from 10mm to 15mm. Length is approx. 21". I appreciate the help.