People at 120,000 years ago liked seashell jewelry but, the question arises, what did they use for string?:
One hundred sixty millennia ago, people were collecting shells but, apparently, not doing much else with them. By 120,000 years ago, people had started stringing shells together and decorating them with red ocher. What changed in that 40,000 years? According to Bar-Yosef Mayer and her colleagues, someone invented string.
If you’re not an archaeologist, dating the invention of string might sound esoteric. But twisting plant or animal fibers into thread is the key to a lot of other technologies, from clothes to seafaring. Kiona N. Smith, “120,000-year-old necklace tells of the origin of string” at ArsTechnica
They appear to have twisted flax stems (the plant from which linen is derived). From the paper:
A second set of experiments was aimed specifically at studying traces produced through the use of perforated shells as strung items. We produced strings from wild flax, tied them through the natural holes in Glycymeris by various methods, and put them in simulative settings where they hung loosely or were strung with knots, to create wear patterns produced through different binding modes. The patterns created by the strings and by shells rubbing against each other were then observed and documented (details in S1 Methods in S1 File).
Paper. (open access)