I finally decided to test out the pigments I found in Chefchaouen.  I tested four colors using water alone, white watercolor paint and white oil paint.  The cobalt seemed to work great with just water.  It dissolved quickly, was smooth and was very opaque.  Without testing it over weeks/months/years, I’m not sure how well it would hold up without the binders and other ingredients usually found in paint.

The other pigments were very grainy in water alone and did not dissolve as well.  In white watercolor paint, they all seemed fine.  The same was true for the oil paints.  The cobalt, however, was the smoothest in all mixtures and seemed to blend really well.  Burnt sienna was the most difficult to mix.

When mixing the lavender, I noticed that it had pockets of lilac and maybe cobalt in it, so I thought maybe I had simply received a mixture of those two pigments in one vial.  I tested this by mixing my own cobalt and lilac.  Sure enough, the color is pretty close to lavender (see the last streak on the right).

So far, I have used the cobalt pigment in this painting only (this one), but I used it sparingly and in very diluted quantities.  More later as these are tested in actual paintings.