Image Attributions:

Jefferson Memorial (https://www.flickr.com/photos/bootbearwdc/32971256/) - dbking - License: Attribution (http://creativecommons.org/licenses/by/2.0/)

Andesita / Andesite (https://www.flickr.com/photos/miguelveraleon/2707246335/) - Miguel Vera - License: Attribution (http://creativecommons.org/licenses/by/2.0/)

Granite (https://www.flickr.com/photos/demartigny/5371613164/) - Charles de Mille-Isles - License: Attribution (http://creativecommons.org/licenses/by/2.0/)

Sphalerite-pyrite (zinc ore) (Faro Deposit, Lower Cambrian; metamorphosed in the Late Cretaceous; Faro Pit, Anvil Mining District, Anvil Range, southern Yukon Province, northwestern Canada) 2 (https://www.flickr.com/photos/jsjgeology/15318984654/) - James St. John - License: Attribution (http://creativecommons.org/licenses/by/2.0/)

Drill Lines (https://www.flickr.com/photos/pavdw/9935839534/) - Me in ME - License: Attribution (http://creativecommons.org/licenses/by/2.0/)

Chert ("flint") 2 (https://www.flickr.com/photos/jsjgeology/16824872035/) - James St. John - License: Attribution (http://creativecommons.org/licenses/by/2.0/)

Slates (https://www.flickr.com/photos/farcloser/4320334762/) - far closer - License: Attribution (http://creativecommons.org/licenses/by/2.0/)

Marble (https://www.flickr.com/photos/121538236@N06/16744029599/) - AC_RT - License: Attribution (http://creativecommons.org/licenses/by/2.0/)

columnar basalt (https://www.flickr.com/photos/pauljill/34524598664/) - Paul and Jill - License: Attribution (http://creativecommons.org/licenses/by/2.0/)