I actually use colored nylon coated steel wire when crocheting jewelry (which I do rarely) but I also use heavier glass & stone beads generally 6, 8 and 10mm sizes and tighter stiches than most instructions state. When I was first learning the technique I used prewaxed cotton cord, nylon, or silk that was specific for jewelry making. I've found from other projects that the embriodery threads tend to deteriorate or fray easily when used on jewelry other than tighly knotted "friendship" or "sailor" style pieces even when using seed beads. Also most books and online instructions suggest using 26gauge or thinner wire that I found too easy to kink coming off the spool if not watched carefully.