The professor describes a process for making glass disks. Summarize the process

Now listen to part of a lecture in an archeology class.
    Professor:
    You see, there were two stages of glass making. The primary production stage, where they made disks of raw glass, and then there was the secondary stage where they melted the raw glass, the glass disks, and created decorative objects or whatever.
    And from this new Egyptian site, we’ve learned that the primary production stage had several steps. First, they took quartz, a colorless transparent mineral and crushed it. Then they took that crushed quartz and mixed it with plant ash. Plant ash is just what it sounds like, the ash that is left over after you’ve burned plant material. They slowly heated this mixture at a relatively low temperature in small vessels, containers like jars made out of clay, and that yielded a kind of glassy material. They took this glassy material and ground it up into powder and then they used metallic dye to color it. After that, they poured the colored powder out into disk-shaped molds and heated it up to very high temperatures so that it melted. After cooled, they break the molds, and inside there were the glass disks.