This is a technique I’ve developed for adding gemstones to a painting.
I took a sheet of watercolor paper and painted a lot of different streaks on it. I don’t remember what kind of brush I used, but it was some kind of flat. I wanted a range of line styles, so I wet the paper in a few places to get more bleed. I also crisscrossed the lines in several places.
Now when I need a gem, I cut it from this sheet. Sometimes I will cut the shape out of a blank piece of paper that I can overlay as a stencil and see what the resulting gem will look like.
After cutting out the shape I glue it onto the painting using a thick acrylic gel medium.
I’ve used this technique a few times and really like the result.