A HANDBOOK OF ROCKS
PART I THE FUNDAMENTALS 1 ROCKS AN OVERVIEW 2 ROCK FORMING MINERALS 8 ROCK TEXTURES AND STRUCTURES 18 FOSSILS IN ROCKS 29 SECONDARY ALTERATIONS IN ROCKS 31 WEATHERING CRUSTS 34 EQUIPMENT NECESSARY FOR ROCK IDENTIFICATION 37 APPROACHING ROCKS INTELLIGENTLY 38 ADDITIONAL RESEARCH METHODS FOR ROCKS 43 PART II IDENTIFICATION KEY 45 LAYOUT AND LOGIC OF THE KEY 46 PREREQUISITES AND INSTRUCTIONS FOR USE 47 IDENTIFICATION KEY WITH ILLUSTRATIONS 50 CONTENTS PART III AN INTRODUCTION TO ROCK CLASSIFICATION 160 IGNEOUS ROCKS 1 PLUTONIC ROCKS PLUTONITES 161 IGNEOUS ROCKS 2 VOLCANIC ROCKS 163 SEDIMENTARY ROCKS 165 METAMORPHIC ROCKS 167 THE FUNDAMENTALS PART 1 1 ROCKS AN OVERVIEW CRYSTAL MINERAL ROCK EVERYONE KNOWS THAT MINERALS AND ROCKS HAVE A LOT TO DO WITH ONE ANOTHER AND THAT MINERALS AND CRYSTALS ARE CONNECTED HOWEVER PRECISELY WHAT A MINERAL A ROCK AND A CRYSTAL ARE IS OFTEN NOT SO CLEAR BEING ABLE TO KEEP THESE CONCEPTS SEPARATE IS HOWEVER OF THE UTMOST IMPORTANCE WHEN WORKING WITH THIS IDENTI CATION KEY HERE ARE SOME CONCISE EXPLANATIONS CRYSTALS CRYSTALS ARE SOLID SUBSTANCES WITH A REGULAR ATOMIC STRUCTURE AND A SPECI C COMPOSITION OF ATOMS AND OR MOLECULES CRYSTAL LATTICE WHETHER OR NOT THIS CRYSTAL LATTICE MANIFESTS ITSELF OUTWARDLY VIA REGULAR CRYSTALLINE SURFACES IS REALLY NOT IMPORTANT EXAMPLE ICE FROZEN WATER H2O EACH PIECE OF ICE HAS A CRYSTALLINE STRUCTURE INCLUDING THE BEAUTIFULLY FORMED STAR SHAPED SNOWFLAKE AND THE ROUND GRAIN OF RN SNOW GRANULAR SNOW FOUND AT THE TOP OF A GLACIER AS WELL AS THE IRREGULAR CHUNK OF ICE FROM A GLACIER ITSELF MINERALS MINERALS ARE NATURAL INORGANIC SOLID CRYSTALLINE BODIES ALL MINERALS ARE THEREFORE ALSO CRYSTALS EXAMPLE QUARTZ SIO2 A ROCK CRYSTAL WITH BEAUTIFUL REGULAR SURFACES IS COMPOSED OF EXACTLY THE SAME MINERAL AS THE IRREGULARLY SHAPED GRAINS OF QUARTZ IN GRANITE OR THE ROUNDED QUARTZ GRAINS OF SAND WHICH AFTER THE WEATHERING OF THAT GRANITE AND A LONG JOURNEY DOWN A RIVER ACCUMULATE ON AN OCEAN BEACH ROCKS ROCKS ARE COMPOSED OF MINERALS ROCKS CAN ALSO CONTAIN FOSSILS LIQUID INCLUSIONS CAVITIES GLASS RESIDUAL ORGANIC SUBSTANCES OR EVEN PIECES OF OTHER ROCKS SUCH AS PEBBLES IN CONGLOMERATE SOLID ROCK AND UNCONSOLIDATED ROCK ARE GENERALLY DISTINGUISHED A BANK OF GRAVEL BY A RIVER IS ALSO CONSIDERED ROCKS BY GEOLOGISTS MANY ROCKS ARE MADE UP OF SUCH SMALL CRYSTALS THAT THEY CANNOT BE DISTINGUISHED AS SUCH EVEN UNDER A GOOD MAGNIFYING GLASS GEOLOGISTS CALL THESE MICROCRYSTALLINE ROCKS ROCKS ARE DIVIDED INTO THREE LARGE FAMILIES IGNEOUS ROCKS SEDIMENTARY ROCKS AND METAMORPHIC ROCKS ROCKS ARE RELATED TO EACH OTHER VIA GEOLOGICAL PROCESSES IN MANY DIVERSE WAYS A SEDIMENTARY ROCK CAN BECOME A METAMORPHIC ROCK AND INDEED IT CAN EVEN RETURN TO A MOLTEN STAGE WHICH LEADS TO THE FORMATION OF AN IGNEOUS ROCK 2 3 A HANDBOOK OF ROCKS