Skull melting is the method used to grow cubic zirconia. Radio-frequency heating melts the zirconia, and a cooled outer layer of unmelted powder, the 'skull', holds the melt.
In more detail
Makers add a stabilizer, usually yttria or calcium oxide, so the crystal stays cubic. Other added elements give colored crystals.
Related terms
- Cubic zirconia: Cubic zirconia (CZ) is a man-made diamond simulant. GIA names it as the most common simulant today.
- Synthetic gemstone: A synthetic gemstone is made in a laboratory and has essentially the same chemistry and properties as the natural gem. A synthetic ruby is ruby, made by people.
- Simulant: A simulant is a material that looks like a gem but has a different chemistry, structure and properties. Cubic zirconia, moissanite and glass are diamond simulants.