Old agate beads are genuine and valuable; If the real thing is collectible, it must be well preserved! In addition, it depends on age and technology. Old agate beads are collectible, but their economic value depends on their appearance.
Old plastic beads are worthless, and the old plastic is only a few decades, because plastic is a modern compound, which is worthless. If it is jewelry agate, it will be especially valuable.
Old glass beads are very valuable. The history of traditional ancient glass manufacturing in China can be traced back to the Western Zhou Dynasty. The colors of glass are varied, and the ancients also called it "five-colored stone". By the Han Dynasty, the production level of glass was quite mature. However, the smelting technology is in the hands of the royal nobility and has been kept secret.