Revelation 4:3

An Understandable Version (2005 edition)

And He who was seated [on it] appeared like jasper [i.e., possibly diamond. See 21:11] and carnelian [i.e., possibly a brilliant red stone], and there was a rainbow, resembling an emerald, surrounding the throne.

Cross References

Revelation 21:11

It had the splendor of God [shining from it], and was as brilliant as a very precious stone, as crystal-clear as jasper.

Revelation 10:1

And I saw another mighty angel coming down from heaven. He was covered by a cloud and there was a rainbow above his head. His face was like the sun and his legs were like pillars of fire.