John the Apostle
Revelation 21:19ASV·traditional attribution

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;

Matthew Henry Presbyterian

We have already considered the introduction to the vision of the new Jerusalem in a more general idea of the heavenly state; we now come to the vision itself, where observe, I. The person that opened the vision to the apostle - one of the seven angels, that had the seven vials full of the seven last plagues, Rev 21:9.

Commenting on Revelation 21:9-27

Jamieson-Fausset-Brown Reformed

And--so Syriac, Coptic, and ANDREAS. But A, B, and Vulgate omit. Compare Rev 21:14 with this verse; also Isa 54:11. all manner of precious stones--Contrast Rev 18:12 as to the harlot, Babylon. These precious stones constituted the "foundations." chalcedony--agate from Chalcedon: semi-opaque, sky-blue, with stripes of other colors [ALFORD].

John Gill Reformed Baptist

The fifth, sardonyx,.... Which is partly of the sardian, and partly of the onyx stone, which resembles a man's nail, from whence it has its name; it is reddish, bordering on white; it may be thought to answer to the onyx in the breastplate, on which was written the name of Joseph.