.. in Acts referring to “Lydia seller of purple”. Sources of purple in Biblical times in addition to Murex were “Trumpet Shells” or “Purple Fish”. These were shellfish, whose shells would be cracked to dig out a vein that held purple mucus that could be spread on silk.
It took about 8500 “Purple Fish” to yield 1 gram of dye, and was also reserved for royalty.
(image: Murex mollusks of various types)