15” rock crystal beaded, with faceted onyx necklace on a 10k yellow gold chain!

I was a little surprised to see the 10k stamped on the clasp! Marked 10k, and signed "Esemco”, 15" inches long. The clear crystals are 12mm and faceted. I was also surprised to learn that the spacers in the middle were faceted onyx! So the crystal/onyx are strung on a 10k yellow gold chain. This is a heavy necklace! Similar ones online are really high priced ($895+) One of the clasps is NOT 10k. It looks like it was replaced at some point. Very vintage and very art deco 💎gemstone, 14k, silver, gold, estate, ring, pendant, earrings, loose, natural, genuine, synthetic, lab, diamond, moissanite, vintage, real, gemstone jewelry, engagement, anniversary, promise, wedding, plated, gem, necklace, broach, fire, crystal, jewel, gift, authentic, collectable, affordable, tested, luxury, natural, opal, emerald, aquamarine, topaz, sapphire, tourmaline, zircon, spinel, investment, ruby, alexandrite, stamped 💎