Before the Islamic Golden Age, glass bangles were generally monochromatic, simple, and unadorned pieces but by the 9th century, twisted glass rods wrapped with various colored glass were being made. By the 3rd century, mosaic glass with various color combinations of blue, green, yellow-green, yellow, orange, red, white, black, etc. was being made. Such mosaics were widely distributed as traded goods in the oasis cities of the Sahara Desert and the Gulf Coast region.