High quality ruby.

They can be integrated directly into the metal clay and resist in the kiln at temperatures of 940 ° for 1 hour.

Despite all our precautions, a spinel may change color during firing. This can be caused by different factors: the structure inside the spinel was not stable enough to withstand the temperature, the furnace overheated or the fact of embedding it in the metal clay can accumulate heat further. We recommend exposing it to high temperatures to test whether it resists before incorporating it into the metal clay.