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�00 <br /> "TWINING <br /> CONCRETE INSIGHT <br /> Morrison Quarry Rock Petrography Page 61 <br /> 4.9 Rock Sample HDR-005 (191.0-191.8): Biotite Gneiss <br /> Received Condition <br /> The sample is a cored rock fragment that measures —60 mm (2 % in.) in diameter and <br /> —220-250 mm (8 % - 9 7/8 in.) in length (Figure 4.9a). Both ends of the core are fractured <br /> surfaces and the side surfaces are rough cored surfaces. The core was received intact in one <br /> piece. No weathered surfaces are present. <br /> Polished Slab <br /> The rock on the polished surface is off-white to pale pink and bluish-gray to bluish-black <br /> (Munsell Soil Color 2.5YR 6-8/1 and GLEY 2 2.5-4/5PB) and predominantly consists of <br /> quartz, biotite, muscovite, and orthoclase feldspar, with smaller amounts of talc and chlorite <br /> (Figure 4.9b, Figure 4.9c). The rock sample exhibits a well developed gneissose structure <br /> with alternating felsic (quartz, feldspar) and darker mineral layers (biotite, chlorite). Gneissic <br /> layers measure up to —100 mm (4 in.) thick and are laterally continuous. Quartz and biotite <br /> grains are coarse grained and exhibit a somewhat pegmatitic texture. The rock sample <br /> exhibits a few randomly oriented quartz-filled and talc-filled veins. The majority of the rock <br /> sample is hard and competent, and exhibits a Mohs hardness of 3-4+. A few talc-rich areas <br /> exhibit a Mohs hardness of<2. <br /> Thin Section <br /> The rock is a high-grade metamorphic rock classified as a biotite gneiss (Figure 4.9d, <br /> Figure 4.9e). The sample consists of major amounts (>10%) of medium to coarse grained <br /> quartz, biotite, muscovite, and orthoclase feldspar measuring up to —25 mm (1 in.) in <br /> diameter. Minor amounts (1-10%) of talc and chlorite is observed, and trace amounts (<1%) <br /> of opaque minerals is also observed. Quartz and felspar grains are subhedral to anhedral in <br /> shape and occur as segregated felsic layers. Biotite and chlorite grains are elongated in shape <br /> and exhibit a preferred orientation. Talc occasionally fills randomly oriented veins <br /> throughout the sample. <br /> Sample HDR-005(191.0-191.8): Biotite Gneiss <br /> Major minerals Quartz(-50-60%),biotite and muscovite(-20-301/o),feldspar(-10-20%) <br /> (10-100%by volume of rock) <br /> Minor minerals Talc(-5-10%),chlorite(-5-10%) <br /> (1-10%by volume of rock) <br /> Trace minerals Opaque minerals <br /> (<1/o by volume of rock) <br /> Report No. 227893.d 22 November 2022 <br />