Word To Use Today: zaffer.

Zaffer is obtained by roasting some fairly poor-quality cobalt oxide: or, if you haven't got any cobalt oxide handy, some low-quality cobalt arsenate will do. 

It doesn't sound very interesting or lovely, but it is, because zaffer can be used to prepare smalt, which is the stuff that makes glass blue:


photo by Arpingstone

Zaffer has also been used in blue enamel and, in the form of a glaze, on blue and white pottery.


Jingdezhen vase, about 1415. Photo by World Imaging, 

So much beauty from a lump of contaminated rock.

Zaffer used to be used in alchemy. 

I think it's of the discipline's great successes, too.

Word To Use Today: zaffer. This word has been around since the 1500s, and comes from the Italian zaffera. It's perhaps something to do with the word sapphire.