CLAY: The Mother of our Inventions

When we grab a 25-pound bag of clay, unwrap it, then push it, pull it, extrude it and coax it into molds, how much attention do we give to its birth, its source? This fantastic, malleable medium has had a life of its own for thousands of years before it arrives in the studio to become the mother of our inventions.

In Native American terms, clay is our "mother" to be honored and engaged with in a dance of creative endeavor. Starting millions of years ago, clay originated as deep-seated, igneous or metamorphic rock. Volcanic eruptions, hot gasses and water infiltration contributed to changes in the rock, from hard to soft, gradually creating clay deposits. Clays in central Minnesota are formed from Precambrian bedrock-mostly basalt overlaid by sandstone—but the oldest Precambrian rock is Archean, primarily granites. Granite actually gives birth to a pure clay: kaolinite. Most natural clays, as they are dug, originate from rocks other than granite and are not pure clays.

Digging and cleaning clay can be a fun activity. Check out excavation sites, local fields or streambeds. These clays may need to be
modified. Some clays are sticky and need the addition of kaolin. Hand-dug clays can also be crumbly. Mixing in other clays provides a greater range of particle size. Good cleaning and screening are essential.

Most commercial clays are carefully prepared compositions, rarely from one source. This ensures that the bag you open today will closely match the bag you opened last week.

Honor the "mother" in your hands. No matter how she arrives, she's come a long way and has lots to teach us!

by Sheila A. Menzies
Tile Heritage Foundation

HTA, 34 Thirteenth Avenue NE, Minneapolis, MN 55413
Email: info@handmadetileassociation.org Phone: 612-781-6409