> On Nov 02, 2010, at 05:22, nigel mccarty-eigenmann wrote:
> 
> > What mineral contents would make a brick come out of the oven blue,
> > green
> > and black?
> 
> 
> Usually, bricks are only colored on the surface by applying a glaze
> (called "slip") to the green brick before firing.  Coloring the brick
> paste itself is generally cost-prohibitive, but it can be done.
> 
> Blue - usually cobalt oxide
> Green - probably some combination of chrome, cobalt, or uranium
> oxides, depending on shade and firing method
> Black - perhaps iron oxide in a reducing fire, but it might tend to
> change color as it ages

You get different coloured bricks from different minerals in the clay you
make the bricks from.  I know of yellow, almost white and red from my own
window.  All Victorian or older.  I had heard of green and blue, but I
wasn't sure if they were regional or custom.

Listmind can always supply an answer :)

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