Vintage Multi-strand Graduated Marbled Cream Beaded Necklace UV

Vintage Multi-strand Graduated Beaded Necklace in a marbled cream lucite plastic Glows under UV light so may it's not plastic ? 5 strands, well constructed Latch closure Weight 108g Length unclasped 21in Drop to first strand 8in - 10in Width 1.4in Condition is great. Appears the clasp has been altered so it is a lobster clasp attached to a spring ring clasp. It was likely a hook and latch closure as the original. Neutral boho statement necklace