Starbucks' remodeled store in Seattle (from the Seattle Times)
Blackboard slate came primarily from Lehigh and Northampton counties in Pennsylvania. The metamorphosed stone began as a sediment deposited in an ocean, when rivers carried clay, silt, and sand off North America and out into a deep marine basin. The 450-million-year old sediments first formed into shale, followed tens of millions of year later by metamorphosis to slate, under thousands of feet of rock. At present, up to 7,000 feet of slate beds make up the valleys and ridges around Pen Argyl, 60 miles north of Philadelphia.
Pennsylvania slate (from Penn Big Bed Slate Co. Inc. web site)
Smooth, durable, and uniform, slate took chalk easily and legibly, didn’t absorb water, and stayed straight and true. By 1905, the majority of blackboard makers in the United States sold boards of slate. Six years later, the Cyclopedia of Education reported on blackboards that “It is doubtless no exaggeration to say that [slate]…should be used for all brick, stone, or concrete buildings.”
Blackboards are a wonderful teaching tool. They don’t break or warp. They can be cleaned indefinitely, either with an eraser or with your hand. They produce a pleasing click-clack sound when written on properly. Often taking up an entire side of a room, they provide a huge space for jotting down anything from music to drawings to numbers. They also seem eternal and permanent. Just think of the photographs of Einstein, or any number of mathematicians and physicists, writing out elaborate equations on a blackboard and you will recognize the role they have played in education and communication.
Or consider how our use of blackboards has seeded our language. We wipe the slate clean or start over with a clean slate. We chalk up something to experience. We refer to a tabula rasa, literally a scraped tablet, but more often defined as a clean slate. We vote for one of a slate of candidates. We are slated to do something and those who had a debt were formerly said to be on the slate. No other stone has contributed a comparable literary etymology.
I am happy to see the reuse of the slate from Garfield by Starbucks. I am lucky to have my own slab of that slate as well. The only downside is that Garfield now has those ugly, petroleum based whiteboards instead of the wonderful blackboards of my youth. Perhaps the school district can be inspired by Starbucks and reuse slate. It is certainly more environmentally hip than whiteboard.