I have always been a fan of Disney's Atlantis animated movie, and ever since seeing it i have wanted my own crystal. This instructable outlines how I made mine. I made two versions of the necklace. One is a cast resin version, and the other is a quartz crystal version.
Step 1: Master Copy
For the resin version I made the master copies of the crystal and crystal holder out of urethane foam. To make the crystal piece I simply took a couple blocks and sanded it down with some sand paper. For the holder I turned a small chunk on my lathe to get the form.
Step 2: Molding
I then took the parts and made molds for them in Oomoo 25. Pretty straight forward I just used some hot glue and plastic mold boxes taken from around the house. Then I mixed up the Oomoo and poured it over.
Step 3: Castings
The castings are cast in Smoothcast 325 with pigment to change its color.
Step 4: Wax Form
I used the same mold I used for the resin crystal holder and made a wax version. Then using the lost wax casting method I made a plaster mold of the wax part.
Step 5: Brass Casting
After melting the wax out of the plaster mold I melted some brass and poured it into the empty cavity of the plaster mold. Once it cooled I dunked the freshly cast piece in water and broke up the plaster.
Step 6: Finished Piece
Once I cleaned the casting up I attached it to a quartz crystal I purchased off of ebay. I added a chain and then the Atlantian Crystal is complete.