Wow I didn't expect ever to come across this.
Whitby Jet is fossilized wood (from 'Monkey Puzzle' trees) and is a very intense black colour, thought to be where the phrase 'Jet Black' comes from. It is found in various places around the world however the finest quality comes from the North East of England around a place called Whitby, where you will also find the world's finest fish and chips but that really is very subjective.
Jet is a good material for carving and polishes very well and that is its primary use, the Jet used in this paint is sourced from the workshops where the carving is done.
So to the paint itself, in masstone it is a deep black, it has decent body and stands up on the palette. It is gritty in texture and again like other Wallace Seymour earths feels like you are painting with crushed rocks, a real part of the landscape, it has soul.
A gentle tinter, it produces warm greys when mixed with white. Used thinly almost as a glaze, the lignite present in the Jet shows up and it produces chestnut, umber-type hues.
Technical Overview
Pigment - Whitby Jet Genuine
Opacity - Semi-Opaque
Binder - Single Estate Artisan Linseed Oil