GIA J UNIOR GEMOLOGIS T Boy SPcouts of Ame rica ROGRAM™ Me rit Ba dge S e rie s : Ge ology GEOLOGY AND GEMS Geology is the science and study of the Earth, its composition, structure, physical properties, history, and the processes that shape it WHAT IS ROCK? • A rock is a solid material made up of minerals • Rocks are the building blocks that make up the earth • Rocks tell a story about the earth and how it was formed IGNEOUS ROCK Eruption of Mount St Helens volcano,1980 Pumice Igne ous rocks s ta rt out in a molte n or s e mi-molte n s ta te a nd be come s olid whe n the y cool IGNEOUS ROCK FORMATION extrusiv e intrus ive IGNEOUS ROCKS Granite Lava S EDIMENTARY ROCK Sandstone S e dime nta ry rocks a re forme d by la ye rs of s e dime nts s que e ze d a nd pre s s e d toge the r ove r a long pe riod of time METAMORPHIC ROCK CONVICT LAKE, CALIFORNIA Slate Me ta morphic rocks ve the ir ma ke up, te xture , or s tructure cha nge d by gre a t he a t, pre s s ure , or both METAMORPHIC MOUNT CHO OYU, NEPAL (26,906 ft.) Marble with spinel DEFORMATION OF ROCKS • Rocks are continually being subjected to forces that bend them • A fold can be defined as a bend in rock that is the response to compressional forces • Folds are most visible in rocks that contain layering GEMOLOGY Ge mology is the s cie nce , a rt a nd profe s s ion of ide ntifying a nd e va lua ting ge ms tone s It ma y be cons ide re d a bra nch of mine logy WHAT IS A GEM? Beautiful Rare Durable GEMS TONE FAMILIES Group • A family of gems from several closely related mineral species Species • A broad gem category based on chemical composition and crystal structure Variety • A subcategory of species, based on color, transparency, or phenomena (an optical effect, like a star in star sapphire, or the blue sheen in moonstone) INCLUS IONS Inclusions can be a variety of objects enclosed within a gemstone or those that extend into it from the surface Inclusions can be: • Other minerals “Lily-pad” inclusion in a peridot • Gas • Liquid Three-phase inclusion in an emerald INCLUS IONS IN ORGANIC MATERIAL Inclusions can also be found in organic material: • Leaves • Bugs such as termites, mosquitoes, or ants • Tree bark PHENOMENA S ome ge ms dis pla y s pe cia l e ffe cts whe n the y inte ct with light The s e s tone s a re ca lle d phe nome na l ge ms be ca us e the y dis pla y unus ua l optica l e ffe cts INCLUSION ACTIVITY CAREERS IN GEMOLOGY COMMERCIAL USES FOR ROCKS AND MINERALS US ES FOR IGNEOUS ROCKS US ES FOR S EDIMENTARY ROCKS US ES FOR METAMORPHIC ROCKS INDUS TRIAL AND COMMERCIAL MINERAL US E INDUS TRIAL AND COMMERCIAL MINERAL US E Pho to c re dits : J oel Beeson Richard D Fisher Chuck Fryer Tino Hammid, Gary Hill Tory Kooyman Pacific Studios, Newport, Oregon Valerie Power Maha Tannous Parke D Snavely, J r of the USGS Eric Welch Robert Weldon