Omya, whose name comes from a village in France, is one of the world's largest producers of calcium carbonate--that is to say, finely ground marble. Taking advantage of Vermont's prehistory as ocean, a period when the calcium-rich bodies of tiny marine creatures accumulated on the ocean floor then metamorphized into limestone then marble, Omya has several quarries that supply their grinding and product formulation plant in Pittsford, from which hundreds of railroad tank cars of calcium carbonate slurry head for the paper, paint, plastics, toothpaste and other industries. By far the largest supplier of marble ore is the Middlebury quarry, which in a century or so will become a pond deeper than Lake Champlain. Already it's the largest object visible from the air in western Vermont.

Once a year, Omya welcomes visitors to a festive set of events that include tours, a chance for kids to play in a huge sand pile, educational displays, and a good feed. Irene and I go every chance we can, partly because the company has no use for pink quartz, and puts a heap of chunks of it where people on the tour can take it for landscaping and home decor. Also, we're fascinated with the way the quarry keeps changing shape in order to remain productive.