This CoorsTek® porcelain bitumen crucible is designed with perforated bottom has a capacity of 28mL. Glazed inside and out except for outside bottom surface and rim. Ceramic bitumen crucibles are designed for similar applications as Gooch crucibles. CoorsTek® porcelain & ceramic labware has excellent thermal-shock resistance. To prevent thermal stress cracks on porcelain ware, CoorsTek® strongly recommends a heating/cooling rate not to exceed 200°C/hour. To prolong the life of your CoorsTek® labware be sure to 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 ceramic labware prior to each use. Do not use any product that appears defective. Hardness of this labware is 57.5 on the Rockwell 45N scale. Refractory Qualities include a fusion point of 1670°C and a softening point of 1400°C. Loaded Temperature Limit of Use (Glazed): 1150°C. Evacuated Temperature Limit: 1300°C. Material: Porcelain. Capacity: 28mL. Diameter: 44mm. Height: 24mm. Filter Paper Diameter: 30-33mm. CoorsTek®# 60170.