Jamieson, Fausset and Brown on Revelation 21:20

20. sardonyx--a gem having the redness of the cornelian, and the whiteness of the onyx.

sardius--(See on Re 4:3).

chrysolite--described by Pliny as transparent and of a golden brightness, like our topaz: different from our pale green crystallized chrysolite.

beryl--of a sea-green color.

topaz--Pliny [37.32], makes it green and transparent, like our chrysolite.

chrysoprasus--somewhat pale, and having the purple color of the amethyst [Pliny, 37, 20, 21].

jacinth--The flashing violet brightness in the amethyst is diluted in the jacinth [Pliny, 37.41].