Stones can have many aliases. This is due to language differences, supplier choice, coloquial trends or slang, or sometimes errors and ambiguity between rocks. Read more here.
|Lapis Black, Nero Angola|
Commercial classification sometimes differs to the scientific, geological designation. In particular, some limestones are deemed marble especially if they take a high polish. Read more here.
MOHS is the standard scale of hardness for minerals 1-10, with 10 being the MOHS of diamond. We also use the broad terms Hard and Soft for simplicity. Read more here.
Angola Black granite is a dark blue anorthosite.
Petrology: Anorthosite: A phaneritic, intrusive igneous rock characterized by a predominance of plagioclase feldspar (90-100%), and a minimal mafic component (0-10%). Pyroxene, ilmenite, magnetite, and olivine are the mafic minerals most commonly present.