Officially the colour range is:
Clear, turquoise, dark green, spring green, amber, yellow, citrin, light blue, mid-blue, cobalt blue, rosalin, amethyst, lilac, smoke.
Although Rosice made black glass, I have not yet seen a SchrÃ¶tter "Lens" vase in that colour, but would not be surprised if they eventually appear.
NOTE: These colour names come from a works catalogue, and Whitefriars colour names should NOT be applied to Sklo Union products. It is both misleading and erroneous to do so.