Row 1: The US stars. They’re hand beaded with silver/blank and blue tube beads in a bias pattern, and often with a silver star on top. Amazing craftwork. They’re used all over the skirt, in vertical rows, as well as on the front bodice.
Row 2: The European stars. Three different sizes are used; the two biggest are around the same circumference, the smallest is a lot smaller (and here also very damaged). They’re made of a lightweight silver plastic, possibly galvanized, and with crystals glued on top. The biggest stars have several levels, creating an amazing shine from all angles.
Row 3: The two first photos shows the Japanese stars. Originally they used the same ones as in Europe, but newer costumes shows a flatter and more glittery version. I suspect beaded, like in the US, but with only silver materials. Opposite, the last one shows how the Aussie/World Tour originally looked: rather round, different sizes, and a bit dark silver in shade. Nowadays they use the European stars.