Cassel Earth is a very dark brown verging on black, transparent paint supposedly used by Anthony van Dyke in his paintings. The pigment is sourced from Germany and the intense brown is due to the presence of lignite and iron/manganese oxides, the same substances present in coal and peat which gives an indication of the hue.
Not to disparage this paint in any way, it has the feel and hue of old engine oil and I can imagine you could build some magnificent Rembrandt type, deep, airy, darks by applying multiple glazes of it.
This version is particularly transparent and quite lean. You could almost glaze with this one straight from the tube.
It is lightfast and slow drying.
Pigment - PBr8
Opacity - Transparent
Drying Time - V.Slow
Binder - Linseed Oil
A proper version of this colour, which is hard to get right. This is a very useful colour in its own right, and ideal for under painting, and giving an option for shadows and blacks.