On Tue, Nov 2, 2010 at 8:22 AM, nigel mccarty-eigenmann <[email protected]> wrote: > Dear Groupmind, > > Anyone know about brickmaking? > > What mineral contents would make a brick come out of the oven blue, green > and black?
Not surprisingly, it's more complicated than just adding a pinch of this to make blue, and a pinch of that makes black. Firing temperature, time to reach that temperature, and atmosphere are all important. The blue Staffordshire bricks that were used in England in the 19th century to make just about everything were burnt in a reducing atmosphere. Browns are produced by the same way, at higher temperature. The same clay, fired in a higher oxygen atmosphere makes red brick. Cream, buff, taupe and yellow are from alkalines (usually lime, but not always) that bind the iron, or from iron poor clays, as in most refractory bricks. I don't know about green. I've never seen one, I dont' think. Zinc, chromium, and cobalt are the obvious guess, though. It's possible to dye bricks after production, too. And modern brick production can do things like put various color modifying chemicals only on the surface of the brick. -- David Scheidt [email protected] _______________________________________________ GurpsNet-L mailing list <[email protected]> http://mail.sjgames.com/mailman/listinfo/gurpsnet-l
