A porous ceramic.

TSCA Definition 2019: High-Alumina cement is a mixture of chemical substances produced by burning or sintering at high temperature (greater than 1200.degree.C (2192.degree.F)) raw materials which are predominantly calcium carbonate, aluminum oxide, silica, and iron oxide. The chemical substances which are manufactured are confined in a crystalline mass. This category includes all of the chemical substances specified below when they are intentionally manufactured in the production of high-alumina cement. The primary members of this category are CaAl2O4, Ca4Al2FeO10, Ca12Al14O33, and Ca2SiO4. Other compounds listed below may also be included in the combination with these primary substances.: CaAl4O7; CaAl12O19; Ca3Al2O6; CaO; Ca3SiO5; Ca2Fe2O5; Ca2Al2SiO7; Ca4Al6SO16; Ca12Al14Cl2O32; Ca12Al14F2O32; Ca6Al4Fe2O15

Localized in atrial & ventricullar muscle fibers of cat heart.