A.T. Robertson Commentary Revelation 21:19

"The foundations of the wall of the city were adorned with all manner of precious stones. The first foundation was jasper; the second, sapphire; the third, chalcedony; the fourth, emerald;" — Revelation 21:19 (ASV)

Were adorned (κεκοσμημενο). Perfect passive participle of κοσμεω as in verse 2, but without the copula ησαν (were), followed by instrumental case λιθω (stone).

With all manner of precious stones (παντ λιθω τιμιω). "With every precious stone." The list of the twelve stones in verses 19,20 has no necessary mystical meaning. "The writer is simply trying to convey the impression of a radiant and superb structure" (Moffatt). The twelve gems do correspond closely (only eight in common) with the twelve stones on the high priest's breastplate (Exodus 28:17–20; 39:10ff.; Ezekiel 28:13; Isaiah 54:11f.). Charles identifies them with the signs of zodiac in reverse order, a needless performance here. See the stones in Re 4:3. These foundation stones are visible. For jasper (ιασπις) see 4:3; 21:11,18; Isaiah 54:12; sapphire (σαπφειρος) see Ex 24:10;. Isaiah 54:11 (possibly the λαπις λαζυλ of Turkestan); chalcedony (χαλκηδων) we have no other reference in N.T. or LXX (described by Pliny, H.N. XXXIII.21), possibly a green silicate of copper from near Chalcedon; emerald (σμαραγδος) here only in N.T., see 4:3 σμαραγδινος, and like it a green stone.