Albert Barnes Commentary Revelation 21:20

"the fifth, sardonyx; the sixth, sardius; the seventh, chrysolite; the eighth, beryl; the ninth, topaz; the tenth, chrysoprase; the eleventh, jacinth; the twelfth, amethyst." — Revelation 21:20 (ASV)

5. Sardonyx. This word does not occur elsewhere in the New Testament. The name is derived from Sardis, a city in Asia Minor (see Barnes on Revelation 3:1), and onux—a nail—so named, according to Pliny, from the resemblance of its color to the flesh and the nail. It is a siliceous stone or gem, nearly allied to the onyx. The color is a reddish yellow, nearly orange.—Webster's Dictionary.

6. Sardius. This word does not occur elsewhere in the New Testament. It is also derived from Sardis, and the name was probably given to the gem because it was found there. It is a stone of a blood-red or flesh color and is commonly known as a carnelian. It is the same as the sardine stone mentioned in Revelation 4:3 (see Barnes on Revelation 4:3).

7. Chrysolite. This word does not occur elsewhere in the New Testament. It is derived from chrusos (gold) and lithos (stone), and means golden stone. It was applied by the ancients to all gems of a golden or yellow color, probably designating particularly the topaz of the moderns.—Robinson's Lexicon.

   However, in Webster's Dictionary it is said that its prevalent color is green. It is sometimes transparent. This is the modern chrysolite. The ancients undoubtedly understood by the name a yellow gem.

8. Beryl. This word occurs nowhere else in the New Testament. The beryl is a mineral of great hardness and is of a green or bluish-green color. It is identical with the emerald, except in the color, the emerald having a purer and richer green color, proceeding from a trace of oxide of chrome. Prisms of beryl are sometimes found nearly two feet in diameter in the state of New Hampshire.—Webster's Dictionary.

9. Topaz. This word does not elsewhere occur in the New Testament. The topaz is a well-known mineral, said to be so called from Topazos, a small island in the Arabian Gulf. It is generally of a yellowish color and pellucid, but it is also found of greenish, bluish, or brownish shades.

10. Chrysoprasus. This word does not elsewhere occur in the New Testament. It is derived from chrusos (gold) and prason (a leek), and denotes a precious stone of greenish golden color, like a leek; that is, “apple-green passing into a grass-green.”—Robinson's Lexicon.

    “It is a variety of quartz. It is commonly apple-green, and often extremely beautiful. It is translucent, or sometimes semi-transparent; its hardness little inferior to flint.”—Webster's Dictionary.

11. Jacinth. This word does not elsewhere occur in the New Testament. It is the same word as hyacinth—huakinthos—and denotes properly the well-known flower of that name, usually of a deep purple or reddish blue. Here it denotes a gem of this color. It is a red variety of zircon. See Webster's Dictionary, under the word hyacinth.

12. Amethyst. This word, also, is found only in this place in the New Testament. It denotes a gem of a deep purple or violet color. The word is derived from a (privative) and methuō, to be intoxicated, because this gem was supposed to be an antidote against drunkenness. It is a species of quartz and is used in jewelry.