Much gem bead material is color-enhanced by any variety of methods including dyeing, irradiating, and heat-treating.
Enhancing gemstones is standard practice and has been occurring for many, many years.
Some more common practices include: howlite dyed to look like turquoise, heated amethyst to create citrine, dyed chalcedony to make "black onyx", synthetic or manmade hematite (hemalyke), color enhanced rose quartz, dyed lapis, dyed abalone shell/mother of pearl, and irradiated blue topaz.