Geology and Stone Identifications

1.0 INTRODUCTION

1.1 Earth is geologically classified as a“stony planet,” as it is entirely stone (rock) of various mineral compositions and forms, excluding its water and atmosphere.

1.2 Earth scientists prefer the term “rock,”1while the commercial stone industry, prefers the term “stone”.2 Both words are correct in their respective frame of reference, and for practical purposes, interchangeable. Every type of rock or stone is composed of one or more minerals. For those who work with dimension stone, it is important to know these minerals—there are about 25 common minerals—that make up the bulk of all dimension stone commonly used. These 25minerals are easy to learn to recognize, and this basic knowledge in turn helps to identify the many varieties of natural stone.

1.3 Identifying the minerals in a particular type of stone is important because the properties and behaviour of stone are the sumtotal of the properties and behaviour of the minerals found in the stone. Knowing something about the mode of formation or “genesis” of a stone further aids predicting the behaviour of a stone. Thus, performance questions can be knowledgeably approached, such as how a particular stone might behave in a given application. Stone industry professionals need this information to reduce waste and avoid costly mistakes.