Gem stones can not be evalutated at a distance and with poor photos. Its too difficult to tell the difference between quality stones and costume jewlery, except for highly recognizable designs. Its too bad the red stone is cracked, but it may not be ruby. Look at it carefully. Are there any scratches on it? If so, it is probably not a ruby. (A ruby is a red colored corrundum, a very hard stone.)

The first ring with a flat top reminds me of a "seal" ring whose purpose was to impart an impression in hot sealing wax for sensitive letters.

The owl ring is a lovely design and is worn. The band my be a gold alloy. Is there a mark inside the band denoting the amount of gold in the alloy. It would read like 12K or 14K (24K is 100% gold). Although an article at 18K gold is considered quality, it is becoming too soft for a ring band.

The white band is interesting. It could be platinum or silver. If it is platinum, chances are the stone is a real gem too because one would not bother with expensive platinum to mount and ordinary costume stone. Some blue, commonly faceted stones are:
Tanzanite
Spinel
Sapphire (natural and lab grown)
Zircon
Diamond
Cubic Zirconia (most often, a lab grown stone)
Iolite

And then, there is colored glass often found in highschool class rings.

Ring #1 is often called a signet ring, a google search will bring up similar items. Rings 2 & 3 do appear to be of some quality, the center stone in #3 if a diamond does appear to be a brilliant cut which is a more modern style of cutting the facets in the stone.