Adam Clarke on Revelation 21:11

Having the glory of God - Instead of the sun and moon, it has the splendor of God to enlighten it.

Unto a stone most precious, even like a jasper stone, clear as crystal - Among precious stones there are some even of the same species more valuable than others: for their value is in proportion to their being free from flaws, and of a good water, i.e., a uniform and brilliant transparency. A crystal is perfectly clear, the oriental jasper is a beautiful sea-green. The stone that is here described is represented as a perfectly transparent jasper, being as unclouded as the brightest crystal, and consequently the most precious of its species. Nothing can be finer than this description: the light of this city is ever intense, equal, and splendid; but it is tinged with this green hue, in order to make it agreeable to the sight. Nothing is so friendly to the eye as blue or green; all other colors fatigue; and, if very intense, injure the eye. These are the colors of the earth and sky, on which the eye of man is to be constantly fixed. To these colors the structure of the eye is adapted; and the general appearance of the earth and the sky is adapted to this structure.