A compact disc that can be recorded multiple times (and erased) is the CD-RW.
When you put data onto a CD, it is called burning a disc. A laser "burns" pits into a dye layer on the disc, making them transparent. These transparent pits can later be read back by the CD drive or audio CD player as data or music.
There are three types of dye used in CD-R discs. The most common is phthalocyanine, and it is usually light green. JVC (formerly Taiyo Yuden) uses cyanine dye. It is usually teal or dark green. Verbatim uses phthalocyanine dye on some discs, and AZO dye on others. AZO dye is usually dark blue or blue-ish silver. The metal layer on the disc is usually made of silver. Archival discs and some professional audio discs use a gold top layer.