RELAÇÕES ENTRE DENSIDADE RELATIVA E DUREZA EM ALGUNS GRUPOS DE MINERAIS ISOESTRUTURAIS, POLIMÓRFICOS E DE SÉRIES ISOMÓRFICAS (DE SOLUÇÕES SÓLIDAS)

Abstract

It is undeniable the importance of the physical properties, density and hardness, for mineral diagnosis, and this study aims to demonstrate the possible proportional relationships that exist between these properties in certain groups of isostructural, polymorphic, and isomorphic minerals. For this, different mineral groups were chosen for the construction of tables, systematically arranged based on ascending density orders, with the intention of scrutinizing the possible variations, or lack thereof, in the hardness property. There was an observation of a lack of proportional relationship between these physical properties for all minerals in some of these groups, but generally with a direct or inverse proportionality between two or more minerals. This result is reinforced by the behavior of isostructural minerals such as in the rutile group, where a direct relationship between rutile and stishovite is observed, while an inverse relationship prevails among the others. The isomorphic hexagonal group of hematite (simple oxides) serves as a pertinent illustration of an inversely proportional relationship between hardness and density. In contrast, the direct proportional correlation between these properties is adequately characterized within the spinel group, particularly evident in the chromite series.