The third picture is as shown on my daughter's little hands.
Step 1: Strip a coat hanger
CAUTION! If you do it this make sure to hold the wire before you turn the drill on. Otherwise the section of wire will turn into a whip / weed wacker. Be careful and work within your experience.
Step 2: Make the ring
Form a circle on a socket bit. Check it against the finger it’s made for for proper fit.
Cut the ring to size and file the ends square.
Step 3: Polish
Spin the socket round and use 400 grit sand paper on the ring. Move on to 2000 grit sand paper and then polishing compound. You can place some electrical tape on the free end of the socket to help keep the ring in place.
Step 4: Make the setting
Cut a ring out and file the free ends so it closes with a nice fit.
Step 5: Solder or glue
Secure the ring in a clamp for soldering. Place the paper clip ring over the seam of the coat hanger ring. Orient the paper clip ring so the opening lays over metal.
Apply flux and drop in a small piece of solder. Use a torch to solder it together.
File off the excess from around the edges. Use 400 grit sander paper on a flat surface to sand down the solder on the setting.
Step 6: Apply the crystal
These particular crystals have a heat activated adhesive backing (350 degrees) and are actually for clothing accents.
Place the crystal over the setting and use a little heat to set it. The adhesive holds very well.
Step 7: Finish
Roll the paper around the bit with the direction of spin for the drill press. Smooth the inside of the ring and any sharp edges.
Buff out any tool marks and polish with polishing compound. I found that a small file, with a piece of sand paper over it, makes short work of stubborn tool marks.
Step 8: Gift
Ideas for the crystal can include a favorite color. Or you can be clever and use the color you get from mixing other colors. For example if your sweatheart's birth stone is red and yours is blue, get a purple stone. Red + Blue = purple.
The entire project, including me taking photos, took less then an hour.
If it's lost, making another will cost about 23 cents. The hanger was free and the paper clip came in a box of 100 for less the a couple dollars.