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WEATHERING <br />FRESH Rock fresh, crystals bright, few joints may show MODERATELY All rack except quartz, discolored or stained. In <br />slight staining. Rock rings under hammer if SEVERE granitoid rocks, all feldspars dull and discolored <br />cystalline. and majority show koolinizotion. Rock shows <br />severe loss of strength and can be excavated <br />with geologist's pick. Rock goes . clunk" <br />when struck. <br />VERY SLlGHT Rock generally fresh, joints stained, some joints SEVERE All rock except quartz discolored or stained. <br />may show thin cloy coatings, crystals in broken Rock "fabri c" clear and evident, but reduced in <br />face s how brig ht. Rock rings under hammer strength to strong soil. In granitoid rocks, all <br />if crystalline. feldspars kaolini zed to some extent. Some <br />fragments of strong rock usually left. <br />SLlGHT Rock generally fresh, joints stained, sand VERY SEVERE All rock except quartz discolored and stai ned. <br />discoloration extends into rock up to 1 inch. Rock "fabric" discernible, but moss effectively <br />Joints may contain cloy. In g r onitoid rocks reduced to • soir with only fragments of strong <br />some occasional feldspar crystals ore dull rock remaining. <br />and discolored. Crystalline rocks ring under <br />hammer. <br />MODERATE Significant portions of rock show discoloration COMPLETE Rock reduced to • soir. Rock • fabric" not <br />and weathering effects. In granitoid rocks, discernible or discernible only in small <br />most fe ldspars o re dull and discolored; some scattered locations. Quartz may be present <br />ore clayey. Rock hos dull sound under hammmer as dikes or s tringers. <br />and shows significant loss of strength as <br />compared with fresh rock. <br />HARDNESS <br />VERY HARD Cannot be scratched with knife or sharp pick. MEDIUM Con be grooved or gouged 1 / 1 6 inch deep by <br />Breaking of hand specimens requires several firm pressure on knife or pick point. Con be <br />herd blows of geologist's pick. excavated in small chips to pieces obount 1 inch <br />maximum size by herd blows of the point of a <br />geologist's pick. <br />HARD Con be scratched with knife or pick only with SOFT Con be gauged or grooved r eadily with knife or <br />difficulty. Hord blow of hemmer required to pick point. Con be excavated i n chips to pieces <br />detach hand specimen. several inches in size by moderate blows of a <br />pick point. Small thin p ieces con be broken <br />by finger pressure. <br />MODERATELY Con be scratched with knife or pick. Gouges or VERY SOFT Con be carved with knife. Con be excavated <br />HARD grooves to 1/4 inch deep con be excavated by readily w ith point of pick. Pieces 1 inch or <br />hard blow or point of a geologist's pick. Hord more in thickness con be broken with finger <br />specimen con be detached by moderate blow. pressure. Con be scratched readily by <br />fingernail. <br />JOINT BEDDING AND FOLlATION SPACING IN ROCK* ROCK QUALlTY DESIGNATOR (RQD)•• <br />Spacing Joints Bedding and Fol iat i o n RQD , as a percentage Diagnostic description <br />Less than 2 in. Very close Very thin <br />2 in. to 1 ft. Close Thin <br />Exceeding 90 Exce llent <br />90-75 Good <br />1 ft. to 3 ft. Moderately close Medium 75-50 Fair <br />3 ft. to 10 ft. Wide Thick 50-25 Poor <br />More than 10 ft. Very Wide Very thick Less than 25 Very poor <br />•Joint spacing refers to the distance normal to the plane of the joints of o single system or • set" of joints that ore parallel to each other or <br />nearly so. The spacing of each • set" should be described, if possible to establish . <br />.. ROD should always be given as o percentage. Diagnostic description is intended primarily for evaluating problems with tunnel s or excavation in rock . <br />ROD = 100 {lengths of core in pieces 4 in. end longer/length of run){1 in. = 25.4 mm; 1 ft. = 0.305 m) <br />KEY TO BEDROCK DESCRIPTIONS <br />LOWNEY ASSOCIATES <br />Environ men to! /Geotechn icol /Engineering Services FlGURE A-2