AlphabeThursday … H is for Hematite

Hematite is red often  called the blood stone; it is a strong and solid stone, it used to burnish gold for this is required a black and dense colour as dark as adamant (a legendary rock or mineral to which many properties were attributed, formerly associated with diamond or lodestone)

It must be sound; without grain.  Then ground on a millstone until it looks like an oversized lipstick with handle that fit comfortably in the palm of the hand. Then it can be used for burnishing gold or silver.  However, when not in use Cennini recommends it is kept in ‘your bosom’ so it will not get  damp; this is not good for the gold.

But also  used when painting frescos. The pure stone is purple but has the structure like vermilion. Once it has been pounded in a bronze mortar it is worked with water until the colour become perfect.  Cennini goes on to say that the colour compares with cardinal, purple or lac but cannot be used with temperas; I wonder why?