The small pebbles are from a bag of decorative sand for fish tanks. The bigger ones are for home decor. They are both transparent plastic and for some reason they hate superglue.
To be honest, superglue can work, but it takes ages. It's better to use hot glue or pva glue.
In the end you only need to glue together everything, it's like flocking. I drybrushed a little of black and gray to show the crystals are being digged out.
