Pigments. From the earth. From rocks and clay soils. This is what I am using to make wood stains.
Here is a simple overview of the process, skipping the most fun part (for me) which is finding the stones in the first place. The stone in my example is sandstone, but a discussion of different stones and ochres and minerals and where to find them (most anywhere, seriously) is best reserved for a dedicated post.
Step one is crushing the rock to smaller pieces. A hammer or simply two harder, larger stones (like the basalt I'm using here) will do the trick. I now use a large cast iron mortar and pestle if I'm at home, outside I still use two rocks and a piece of cloth laid over to catch flyaways.
Note: I always wear glasses when I do this and I always were an N100 mask when I'm grinding pigments. I also now use a portable intake air filter when I grind indoors. It's actually for wood (I use it for hand sanding indoors) but it works well for pigment grinding too. Pigment dust is not something you want in your lungs. Tiny, tiny, sharp shreds of rocks and glass in your lungs anyone?
Then it is filtered in water, called levigation. This is where you add water and swirl it around. Just like soil sample tests, the heaviest bits will sink while the finest particles remain suspended in the water.
Here is a yellow sandstone example where you can also see distinct layers.
Then I pour off the water into a separate, shallow container to allow the water to evaporate, leaving behind only those fine particles which makes a wonderful pigment for a wood stain as the particles are tiny enough to absorb deep into the wood grain.
Then more filtering with adding more water - my end goal is to separate out the fine and medium size particles but leave behind the heavy sand.
On the left (above) is the heavy sand and the right is the fine particles of pigment after levigation and drying. I can still get more pigment from this sand and will repeat the entire process again, leaving behind even paler sand.
Here are the two colors mixed with just water to show their tones. For my work, I make watercolors out of the pigments to help bind the pigment into the wood.
Above is another rock from my grandmother's farm. This one is claystone. Tough to grind (I had to use the granite mortar and pestle, not the one shown here) but no sand in it so yielded pigment more easily.
Some of the reds, orange and yellow colors in this rooster (a gift for my grandmother - for her rooster themed kitchen) were made from rocks on her farm. I love the sense of place that is infused into the work.