I am always looking for new tesserae to create mosaics with, and when I saw the Calliope Series of  Recycled Glass Tile I was hooked!  The variegation is especially enticing, allowing for visual texture, and giving a lively feeling, in motion with swirls.  The sheen is lightly iridized.  According to Hakatai, the Oregon Importer of these tiles, they are 50% recycled glass, 90% of which is post-consumer.  As soon as they arrived, I was in the studio experimenting.

I also have a sheet of Garden, in shades of blue and green.