Rev 4:3

“At last there has really been found a way to prevent even gold from being loved! We have also seen at Rome the nobility of gems blushing in the presence of our matrons at the contemptuous usage of the Parthians and Medes, and the rest of their own fellow-countrymen, only that (their gems) are not generally worn with a view to ostentation. Emeralds lurk in their belts; and the sword (that hangs) below their bosom alone is witness to the cylindrical stones that decorate its hilt; and the massive single pearls on their boots are fain to get lifted out of the mud! In short, they carry nothing so richly gemmed as that which ought not to be gemmed if it is (either) not conspicuous, or else is conspicuous only that it may be shown to be also neglected.”

“"And He that sate upon the throne was, to look upon, like a jasper and a sardine stone." Upon the throne he says that he saw the likeness of a jasper and a sardine stone. The jasper is of the colour of water, the sardine of fire. These two are thence manifested to be placed as judgments upon God's tribunal until the consummation of the world, of which judgments one is already completed in the deluge of water, and the other shall be completed by fire. "And there was a rainbow about the throne." Moreover, the rainbow round about the throne has the same colours. The rainbow is called a bow from what the Lord spake to Noah and to his sons, that they should not fear any further deluge in the generation of God, but fire. For thus He says: I will place my bow in the clouds, that ye may now no longer fear water, but fire.”

“Since the rainbow was given as a sign of safety after the flood, it is now suitably used as a sign of the church's reconciliation to God. For when the storm clouds are irradiated by the splendor of the sun, they produce the form of a rainbow. In comparison to this, when the souls of the saints are illumined by the Sun of righteousness, which is Christ, his deity deigns to be reconciled by their intercession.”

“And he who was sitting was like the appearance of a jasper and a sardius stone. Jasper's color signifies water, sardius fire. With these two, we know the judgment is celebrated. For as it was in the days of Noah, so will be the coming of the Son of Man (Matt. 24).”

“And a rainbow was around the throne, in appearance like an emerald. The rainbow, which is made by the sun shining on clouds, and after the flood was first made a sign of propitiation, by the intercession of the saints whom the Lord illuminates, signifies the Church being fortified. They are well compared to the emerald stone of great greenness; for as they expect an imperishable inheritance with perfect faith, they also powerfully protect others by praying.”

“And he that sat, was to the sight like the jasper and the sardine stone. By the jasper, which is green, are represented the green pastures of the paradise; and what are those pastures but Christ's divinity, in which all things live? As the same John said, He that hath the Son, hath life. [1 John 5:12] By the sardine stone, which has a resemblance to red earth, is represented our Redeemer's humanity, because truth is sprung out of the earth. [Ps. 84:12] The species of these stones may also represent the Church. And there was a rainbow round about the throne, like to the sight of an emerald. By the rainbow is represented the reconciliation of the world achieved through the plan of the Word incarnate. Indeed the sun illuminated a cloud and a rainbow appeared, because when the Father's Word, which is the Sun of justice, [Mal. 4:2] shed rays of light on human nature by adopting it, this very adoption of his humanity, which is called a cloud by the prophet, became the reconciliation of the world. The very interpretation of the noun agrees with this, for if you add one letter and say irini, it means "peace" in Greek. When he illuminates the solid hearts of the saints, which are called clouds, they give the appearance of a bow, because they are bent towards piety by the fact of praying to God. There is here a fitting connection of symbols, because below, lightnings and thunders are said to proceed from the throne, as though from a cloud. Then, since a rainbow shines principally with two colors, namely that of water and that of fire, what is represented is either baptism by water and by the Holy Spirit, or the preceding judgment through the flood and the following one through fire. It is in order that it may be shown more openly in this passage that the divinity was propitiated to the world again by him, that it is compared to the sight of an emerald; for this stone is of a very green color, which it is not unfitting to apply to the nature of the divinity.”

“And a spirit above Him resembling jasper and carnelian. God is not like these things; away with that thought [ἄπαγε]. He is unlike any of the things perceived by the senses, neither having a body at all, invisible, spiritual, and without form. The invisible God is like that of the Seraphim, revealing their unseen nature, cover their faces with their wings (Is. 6:2). And to Moses, God spoke, saying: "No one shall see my face and live." (Ex. 33:20) But even the evangelist states decisively: "No one has ever seen God." (Jn. 1:18) Therefore, God was not seen resembling anything; rather, the vision of Him was depicted through the works of God by the Revelation. For the jasper is a precious stone, this one is emerald-like and green, resembling the venom of an asp [ἰῷ ἀσπίδος], from which it also derived its name. The carnelian is another precious stone, fiery and blood-red. The jasper is said to symbolize for us the nourishment of God, and provision, since all nourishment for humans, four-footed animals, birds, and crawling beasts has its origin, and as it were its cause, beginning from green grass. For the prophet says: "He causes grass to grow for the cattle, and vegetation for the service of mankind, to bring forth bread from the earth. And wine gladdens the heart of man, to make his face cheerful with oil." (Ps. 103:14-15) And again, in the creation, God says: "Let the earth bring forth grass, herb yielding seed, and fruit tree yielding fruit after his kind." (Gen. 1:11-12) Now, jasper illustrates these things. But indeed, the carnelian is described as the fearfulness of God; for our God is said by the advocator [ἱεροφάντης] Moses to be "a consuming fire", (Deut. 4:24) and the prophet also cries out to Him: "You are fearful, and who can stand before Your face?" (Ps. 75:8) Accordingly, the wise Apostle writes: "It is a fearful thing to fall into the hands of the living God." (Heb. 10:31) Since the goodness of God is incompatible with those who love sin and are scornful, and is pure, not leading to repentance but to the freedom to commit wrongdoing, it is reasonable that God, along with goodness, also possesses the generous and the awe-inspiring; therefore Paul, knowing the character of those learning and the need for incentives rather than gentleness, addressed the Corinthians, saying: "What do you want? Should I come to you with a rod, or in love and a spirit of gentleness?" (1 Cor. 4:21) Yet one of the saints (Basil) said, "Gehenna does not frighten you; the kingdom does not urge you on? We speak to you with a heart of stone." Therefore, it was known as a fearful and astonishing necessity for those being disciplined. But the carnelian is not the first for God, rather, the first indeed is the jasper. For His nature is that of good and humane and gentle, and He wishes to be a Father rather than a Master to us. But, if it is lawful to say, we 'force' Him, and He leaves behind His natural gentleness, and is led by unnatural sternness. And it is said that a rainbow encircling the throne appeared like an emerald in appearance. The perceptible rainbow [ἶρις] which the divine Scripture calls the bow [τόξον] of God, consisting of the reflection of the solar light, when it is diverted in the thickness of a cloud, has become multicolored and numerous in color. But that one, the spiritual rainbow, which encompasses the divine throne, was of one kind; for it was emerald in appearance. And it itself also prefigures all the holy and ministering spirits of God, wherefore it has also been called rainbow, although it happens to be of one kind, so that from the various colors of the rainbow we may conceive the many orders and distinctions of the divine angels. Everything indeed is bound to one single color; for all things are equally beneficial and bear the likeness of their own Master, of the emerald color that itself attests to its productive power, just as the jasper does to God. And let no one stumble over those who encounter it; Why indeed are the sacred orders of the spiritual beings concerning God are overshadowed by the more precious stone of the emerald, while God Himself is associated with the less precious jasper and carnelian? For the discussion is not now about the value of what is visible, but about the meanings signified by the colors. For if someone were to seek honor in a petty way, there would be nothing for which God could be accused, nor would anyone find fault with it; that is, that the Lord is rejected with a stone. For Isaiah says, "Behold, I am placing a cornerstone in Zion concerning the Lord." (Isa. 28:16) And the prophet speaks of the stone that the builders rejected concerning him. The evil spirits are allegorized as mountains; for David himself said that mountains can be moved—"in the hearts of the seas," and "the mountains were shaken in his mighty power," (Ps. 117:22) whose magnitude is so great that it is impossible to find anything greater than it.”