The ring finger is the finger of Apollo, and equally the finger of the Sun, the two names used interchangeably exactly as they are for the mount at its base. That doubling is itself a piece of evidence. A god-name and a planet-name standing for one thing, either being usable, is how astrological vocabulary behaves, and it shows the chiromantic scheme taking the term ready-made rather than coining it for the hand.
What is read from the finger is what the same system reads from the Sun: art, display, brightness, the wish to be seen and the luck of being noticed. A long, straight, well-formed ring finger is taken for talent and for recognition of it; an over-long one for showiness, or in some manuals for a taste for gambling; a poor one for a life passed without applause. The Sun line, also called the Apollo line, runs up the palm toward it and is read for the same qualities, so the finger, the mount and the line together form a single Apollonian district of the hand.
The wedding ring is worn here across much of the world, and that custom is far older than the modern palmistic system, so the two should not be run together. The reason usually given for it, that a vessel runs from this finger straight to the heart, is true of no human hand. The custom is real and its explanation is folklore, which is exactly the distinction the chiromantic literature is unwilling to draw about its own material.