Model magic or if you can afford it, epoxy clay, wrapped around a 5/8'' oak dowel rod. The only sculpting tools you really need are your hands, some popsicle sticks, and various sizes of paper clips bent into various shaped loops.
To get the dimensions right, print out your ref photo life size and use calipers to compare against your sculpt. cheap calipers are available from harbor freight. They're crappy, but they work.
Smoothing can be done after the clay has hardened with sandpaper. Sand up to 400 grit, prime it paint it white (optional if you used a white primer), then paint the accents (the gold and the pink). Painting the whole thing with a clearcoat will make it more durable, but again, optional.
I'd probably buy the rhinestones. There are websites that cater to jewelry makers that sell plastic gems in all sorts of sizes and shapes at fairly reasonable prices. The alternative is to make a latex mold and resin cast them, but that is a sorta pricey process, and without a pressurization vessel, the resin often comes out cloudy or filled with tiny bubbles.
You can probably salvage the glass shield thingy that encases the crystals in the middle from a random soda or water bottle.