The casting process
This method of casting is called "lost wax casting" and the process has been used for thousands of years. It is infact the oldest method of casting in the world and the earliest examples of it date back to 2500 b.c. and the Royal Tombs of Ur.
The caster starts off with the original shell which is put into a cold mould that is made up of two parts. This then cures for approximately 12 hours. The mould is then split and the original shell taken out. The two halves are put back together and wax is injected into it. This leaves you with the original pattern of the shell but made out of wax. This wax pattern is then put onto a wax tree and put into a flask which is filled with investment powder in a vacuum chamber. This flask is then put into an oven where the wax is burnt out over 16 hours. It is then vacuumed cast in a casting machine, then cooled down. The wax tree is taken out and replaced with molten silver. Once this has completely cooled down you are left with the original pattern in silver.
This silver shell then has to be highly polished, filed and made in to the pieces of jewellery you see here on this website.
Further history of the lost wax casting technique can be found here