Jade, Amber Purple, Aqua, Cobalt, Sky Blue, Black, White, and Clear are made of borosilicate glass. Ocean Blue and Emerald are made of soda lime glass.
Amber purple in smaller sizes like 18g, 16g and 14g are going to be a transparent yellow/amber color.
The average size of the disk is:
Jewelry is measured through a gauge system (see chart below). The higher the gauge number the smaller the wire is. A standard "earring" is usually 20 gauge. Jewelry gauges/sizes can vary between manufacturers. There is no universal regulation on companies to make a standard size in body jewelry. A big part of this is that some jewelry is made overseas and measured in millimeters. And in the USA jewelry is measured in inches/gauges. So many times jewelry can be anywhere from .5mm to 1mm different.