Slate is a rock that has many natural color variations including gray, blue, greenish-grey, dark red, black, tan and even purplish-gray. References to the color “slate” most likely mean a medium-dark grey with blue under... More »

Slate streak colors are used in mineralogy studies to classify properties of a mineral based on the shade of its crushed powder. When rubbed against a porcelain slate, minerals leave streak marks that assist in determini... More »

A Maltese, also called the blue tiger, is a Bengal tiger with what scientists call pseudo-melanism. This means that the tiger has a great deal of black pigmentation in the fur. The Maltese tiger is known to be part of th... More » Pets & Animals Mammals Large Cats

To identify a rock, it is necessary to consider its luster, color, hardness, cleavage and density. The geographical location of the rock should also be used to help identify it. More »

Slate usually forms in a tectonic environment when a convergent plate boundary meets a basin that was once made of sedimentary rock. Heat and pressure convert the substances in the basin, specifically shale, to slate. It... More »

Slate is useful for roofing, pool tables and floor tile. At one time, slate was commonly used for school blackboards. When slate forms, it contains parallel lines of cleavage that allow it to fracture into smooth, thin s... More »

Shale, marble, mudstone, slate and well-packed sandstone are all examples of impermeable rocks, which means that water cannot easily pass through them. A large number of metamorphic and igneous rocks are impermeable, as ... More »