10 VISIT OR GUIDE Ser pentinit e Boulder The massi ve serpentine in the small g arden in the center of the front w alk w ay came from the Mother L ode area of the Sier ra Nevada California It is from the same outcrop as the serpentine roc k in the nor th atrium This large boulder is made up of metamorphic serpentine minerals that contain high concentrations of magnesium and iron S erpentine soils and the runof f from serpentinite outcrops can be so acidic that man y plant species cannot survi ve them without the addition of potassium and lime Con ver sely cer tain plant species grow only in serpentine soils Gift from John A Huberty collected b y Christopher W H Hulbe and students from Sacramento City College California through Bennie W T ro x el for mer science editor for the Society Society Seal The S ociety s seal adopted in 1 891 is reproduced on the w all in front of the building It is a gif t from Mr s Barbara Campbell in memory of her husband Ar thur B Campbell 1 9241 971 a F ellow of the S ociety At the time of his death Campbell w as c hief of the branc h of R oc k y Mountain En vi ronmental Geology U S Geological Survey A commemorati ve plaque of the same stone Spar tan Pink granite from a stone quar ry in Georgia is set on top of the w all abo ve the seal Cutting and emplacement of the seal and plaque w ere b y Milton Erickson Erickson Memorial Co Denv er Colorado Before you reach the garnet specimen ahead on your left you will see stairs and a pathway leading down to the Eaton T errace which is located near the southeast side of the building The terrace was made possible through a contribution from Gordon P and V irginia G Eaton From the terrace you can view GSA s staff garden and the southern portion of the Society s land Gar netBear ing Roc k L ooking to the lef t of the serpentine g arden you will see a dark spot ted boulder The red crystals embedded in the roc k are g arnet a complex iron magnesium aluminum silicate mineral Outlining the g arnets are border s of blac k horn blende Small clear crystals of g arnet are highly priz ed as gems but these are not of gem quality they are used for abrasi ves g arnet paper for example is a muc h bet ter abrasi ve than sandpaper and is cor respondingly more expensi ve This monolith is from the main ore z one of the g arnet deposits at Gore Mountain in the southeastern par t of the Adirondac k Mountains of New Y ork The deposit has been mined continuously for more than 1 0 0 year s and is the only commercial source of graded g arnet abrasi ve powder s obtained from a bedroc k deposit Gift from Barton Mines Corporation North Creek Ne w Y ork through Charles B Sclar Lehigh Uni v ersity Bethlehem P ennsylv ania Memor ial F ountain Next you will see giant clam shells fashioned into a fountain The shells are from the largest li ving bi valve Mollusca family They occur in the western and southern P acifc Ocean This display is in memory of Charles L ee McGuinness 1 91 4 1 971 who at the time of his death w as c hief of the ground w ater branc h U S Geological Survey and c hairman of the Hydrogeology Di vision of GS A Gift from the Hydrogeolog y Division of GSA