Gray wedge

Convert the following representation of ethane, C2H6/ into a conventional drawing that uses solid, wedged, and dashed lines to indicate tetrahedral geometry around each carbon (gray = C, ivory = H). 

SPHENE. Thismineral occurs as ayellow, green, gray, or brown calcium titanosilicate, corresponding to formula CaTiSiOj, crystallizing in the monoclinic system. Fracture conchoidal to uneven brittle habit usually wedge-shaped and flattened crystals, also massive and lamellar luster, resinous to adamantine transparent to opaque hardness, 5-5.5 specific gravity. 3.45 3.55... 

The fruit is an achene and generally few are formed (Russell, 1979 Swanton, 1986 Westley, 1993 Wyse and Wilfahrt, 1982). Seeds are x 5 mm long x 2 mm wide, flattened wedge shaped (obovate to linear-obovate), and smooth. Their external color is mottled black, gray, tan, or brown and may have black spots (Alex and Switzer, 1976 Konvalinkova, 2003 USDA, 2006). 

Gray M. B. and Zeitler P. K. (1997) Comparison of clastic wedge provenance in the Appalachian foreland using U/Pb ages of detrital zircons. Tectonics 16, 151-160. 

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