:icon_02: Hi, Kriskris,
It looks like the bouquet is made more or less like this: Take a length of wire about 4 times longer than you want the "stems" in the bouquet to stand. Place a crystal 1/4 of the way down from each end of the wire. Bend the wire over, so its ends meet at the center point, forming 2 stems with a crystal at the end of each. Now (probably holding an end at a time to the center point, using pliers) twist the wire all the way up the stem to the crystal. The twists add that nice texture to the stems, and hold the crystal in place at the end of the stem.
I'm guessing general basemetal wire was used, since so many colors are available. (I doubt many people would be interested in precious metal wire if it were plated odd colors.) Rings & Things sells a good selection of this stuff, if you check in our catalog.
The crystals are Clear AB on the main page. The website also has a link to a selection of the other colors these bouquets are made in, and there it says that the basic prices of the bouquets apply only to Crystal AB. Size is hard to guess, but at least 6mm seems likely. (We also offer good prices on these.)