Blocks of Nero Zimbabwe, also known as absolute black granite, should not scientifically be classified as granites but as gabbros. Leopold von Buch, a German geologist, in 1810 gave the name of gabbro to an intrusive rock found in the hills of the same name on the Tyrrhenian seaside to the south of Livorno. Gabbros and Granites are intrusive magmatic rocks, of volcanic origin, which terminated their cooling process inside the earth’s crust. The difference between the resulting materials is in the percentage of silicates (minerals composed mainly of silicon and oxygen), which leads to differences in color and strength. Gabbros have a silica content ranging from of 45% to 52% and thus are classified as basic rocks. Granites have more than 63% silica thus resulting in acidic rocks. The presence of silica in the granite, acidic rocks, gives them colors that range (approximately) from white to red with a medium grain and other characteristics. Gabbros, on the other hand, being basic rocks, are plagioclases, pyroxenes, amphiboles. What does this difference entail? Generally (and we note that too when we process these materials) the more materials of this type are dark the more they are hard. Nero Zimbabwe, in particular, is known as absolute black due to its color, being a very compact and homogenous rock, a gabbro with a black background dotted with small dark grey crystals.