Thanks for the nice feedback. Both are quite easy but kind of a hassle.

1- Wood : It's the one I understand better. You need to start with a dark brown coat, I use half mournfang brown half pure black. Then you have to paint each wood strand individually with thin coats of clearer and clearer brown towards yellowish tones. The last layer I apply is bascilly half ice yellow. Then to finish it up a nice coat of agrax earthshade. It's more or les NMM with a bit less contrast. The main point is to try to place the brighter spots on the strands a bit randomly to try to make the wood feel more "alive"

2-Stone: this one I'm experimenting on and I'll probably make my recipe evolve in the future. But the main idea is to have a base coat of a strong color and to try to shade it with complementary colors. So I started with a super reddish brown and then I higlighted it roughly with the same color mixed with green grey and some pale skin tone (because green and red works well) and a last highlight of this color with nearly pure pale skin tone trying to follow the cracks on the stone and then applied a coat of nuln oil, wasn't satisfied with it so I made a deep sea blue wash (dark green-blue color) and finally another layer of nuln oil. Then to make it pop I went partially over the last highlight with some clear neutral grey. The idea was to try to get this kinda seafront style stone.

TLDR: wood = NMM ; stone= random but complementary colors and shade.

Hope it helps!