When I was looking for interesting rocks at a local rock shop to grind into pigment I found a piece of anthracite. I knew various forms of coal or related materials could be made into paint, so I thought I’d try it. I don’t know what the lightfastness of this is, but it’s probably not very good. Even so, I really like this slightly brownish black watercolor paint.
The wet on wet swatch is my favorite because it was so inert in the water that it easily retained interesting visual textures. In the light wash you can see that there’s a few very tiny loose particles in the paint. I just wiped one of them off the paper, so maybe I needed to mull the paint longer. The pigment had a little resistance to mixing with the wet ingredients, but not nearly as much as when I tried making viridian watercolor a few weeks ago.
Here’s the tools I used for making the pigment. The mortar and pestle are stainless steel and I only use it for grinding pigment. This is the second time I’ve used it like this. The first time I was doing this exact process but with some pieces of tiger’s eye a few weeks ago.
The goggles are obviously to protect my eyes, since little pieces of anthracite kept flying everywhere. The steel block that the anthracite is on is meant for making jewelry. I ordered it from Amazon specifically for doing this kind of thing. The hammer is 3 lb because with more weight I can move the hammer more slowly, giving me more control, and still have the same impact force.
The anthracite has a lot of interesting textures in it. In some places the pattern of the cracks almost looks like wood, and in other places it’s very glossy and looks like obsidian.
I found that tapping very lightly with the hammer was best, even though it seemed slow, because otherwise the little pieces would fly everywhere. Holding the hammer just below its head gave me more control. I found that holding my hand on one side of the block and tapping with the hammer angled toward that side helped a lot to prevent pieces from flying off the block. It’s not necessary to break it down into a fine powder at this point, a coarse powder is all that’s needed.
Here’s the finished pigment, ground much finer with the mortar and pestle. It turned out to not be as fine as I thought. When I actually put this under the muller to make paint it still felt pretty coarse, but it smoothed out a bit as I mulled it.
I still have most of the anthracite left, which I may grind up later and use to make oil paint.