what is corundum

what is Corundum Corundum mineral, crystalline-alumina (Al2O3), trigonal system, ditrigonal-skalenohedral. Occurs in the form of separate or fused into groups of barrel-shaped, dipyramidal and tabular crystals of pseudohexagonal appearance, isolated impregnations and ...

What is a trough?

What is a gutter? The gutter is: 1) An oblong groove, hollowed out in the WWC, and usually intended to drain water or to dump something. 2) An oblong groove on the ground, in the ground. 3) A long narrow depression on the ocean floor ...