Icon artists, illuminators and others interested in historic pigments for various reasons (such as reproducing the type of paintings done by the Old Masters in the same materials they used) are being served by various companies that make natural and obsolete pigments used in paint formulations.
For watercolor, even in the last 30 years, pigments have changed dramatically. For example, I could still buy genuine gamboge, a yellow pigment from a latex-producing tree of Asia, genuine vermilion, a somewhat fugitive red-orange mercuric pigment and genuine Rose Madder as well as true Manganese blue. Now, no one makes Manganese blue as it is a very polluting metallic pigment; vermilion darkens over time, gamboge and madder fade. Madder is still made by the original method by Winsor Newton and is still beautiful. Others imitate it (Rose Madder Genuine by Daniel Smith) but none has the true red color of W/N's special formulation.
Now, Daniel Smith and others make pigments from ground gemstones, but Rublev (naturalpigments.com) makes the old style paints found in Russian icons and the 18th and 19th century Old Master watercolors. I've been testing them out and they are quite interesting, but..not what you'd expect.
I'll put up reviews of the colors, swatches and my findings in blogs to follow.