I am going to be starting a mosaic project (first one in a loooong time) and have an idea of using some sand that I've collected on a trip to Hawaii in my piece. If you've ever been to Hawaii (or any place with volcanoes) you may be familiar with black sand, which is really crushed lava. It is not as fine as beach sand but it is still very granular — sort of the size of sea salt.
The mosaic is for indoor decoration only (wall hanging). I may or may not use grout in general, at least in some areas. But I would like to use the black sand as an outline (sort of like a magic marker line in a drawing). I'm testing a glue/sand mixture right now but worried about yellowing over time, cleanup, and shrinkage.
I'm scouring the internet for ideas and haven't really found anything solid. Angel, I know you are very knowledeable in the materials used for making stones so thought this would be a great place to post this question.