Materials:
18ct gold vermeil.
Gold vermeil is solid silver plated with a thick layer of 18ct gold. For longer lasting wear I use a 5 micron layer of gold which is around 5-10 times thicker than most vermeil available on the high street.  However, all gold plating will eventually wear off and its duration will depend on how it is cared for.
 
Size:
Ring - UK Size N
Mandala - approx 15mm circle
Amethyst - 2.5mm