Porcelain Crucibles

CoorsTek Porcelain Crucibles are glazed inside and out except for the outside bottom surface and rim. 
Prolonging Labware Life
Follow gradual heating and cooling rates.
Use an oven or hot plate as an intermediate step when quicker heating/cooling rates are required.
Gradually increase flame intensity when using a gas burner.
Avoid contact of heated ware with a cold surface.
Carefully inspect your labware prior to each use.
Do not use any product that appears defective.
 
Hardness
57.5 on the Rockwell 45N scale
Refractory Qualities
Fusion point: 1670° C
Softening point: 1400° C
Limit of use, unglazed: 1400° C
Limit of use, glazed: 1150° C
Limit of use, evacuated: 1300° C