We went to an exhibit titled “Objects of Wonder: From the Collections of the National Museum of Natural History,” an interesting display of items that examines how scientists use the Smithsonian collections to enlighten and illuminate our understanding of nature and human culture. I took a few pictures, but most of it was more appropriate for viewing and reading about than photographing.

This was calcite on quartz (variety amethyst) discovered in Rio Grande do Sul, Brazil. Geodes – hollow rocks lined with crystals – are formed through volcanic activity (and more processes after that).

'Objects of Wonder': What causes the color blue? posted earlier: