1. Jasper (ἴασπις) - various colors
2. Sapphire (σάπφιρος) - indigo
3. Chalcedony (χαλκηδών) - greenish blue, coppery
4. Emerald (σμάραγδος) - green
5. Sardonyx (σαρδόνυξ) - dark with orange, white, or red
6. Carnelian (σάρδιον) - red
7. Chrysolite (χρυσόλιθος) - gold
8. Beryl (βήρυλλος) - uncertain (related to the Hebrew word shoham, possibly "pale" or "striped" - a type of onyx/sardonyx?)
9. Topaz (τοπάζιον) - yellow
10. Chrysoprase (χρυσόπρασος) - green
11. Jacinth (ὑάκινθος) - indigo, as in hyacinth
12. Amethyst (ἀμέθυστος) - purple
Just an idea :)