焦寶石是硬質粘土熟料的別稱，是由生焦寶石（簡稱生焦）經高溫燒結而成的，煅燒后的焦寶石具有化學成分穩、耐火性高、強度大、質地均勻、結構致密、吸水率低、外觀潔白等特點。廣泛應用于粘土質定形和不定形耐火材料、粘土質坩堝、日用陶瓷、鑄造砂、鑄造涂料，建筑陶瓷、硅酸鋁纖維、墻地磚等行業。
Calcined Clay, nickname of hard clay grog, is composed of raw Coke (referred to as raw Coke) with high temperature sintering. The calcined clay has the characteristics of stable chemical composition, high refractory resistance, large strength, uniform texture, dense structure, low water absorption, white appearance and so on. It is widely used in clay shaping and amorphous refractories, clay crucible, domestic ceramics, casting sand, casting coatings, building ceramics, aluminum silicate fiber, wall and floor tiles and other industries.
理化指標：Physical and Chemical indexes
| 主要化學成分(%)Chemical composition(%) |
體積密度（g/cm³） Bulk density（g/cm³） |
|||||
| Al2O3 | SiO2 | Fe2O3 | K2O+Na2O | CaO+MgO | TiO2 | |
| 44-47 | 45-50 | ≤1.2 | ≤0.3 | ≤0.5 | ≤0.8 | 2.55 |
| 43-45 | 43-52 | ≤1.5 | ≤0.4 | ≤0.5 | ≤0.9 | 2.50 |
