Ahh... the fabled handwavium crystals of Mars... such beauty and power...
How do I make some?
Basically, the handwavium crystals are nothing but pink foamboard insulation glued to a thin (1/16" or 1.5mm) plywood base, painted and flocked. I made them in a way that is essentially scale-neutral, like most landforms. In 25/28mm, they are big rocks. In 15mm, they are huge crystals.
Anyway, step-by-step (and yes, I should have taken photos. It was late and I wasn't thinking about the blog. Sorry.):
Make the crystals. I took some scrap pieces of foamboard, and cut them into basically crystalline looking shapes, making sure I kept at least one side as flat as possible. I used a hotwire foam cutter to cut the foam. To make the thicker crystal, I glued two pieces of foam together after cutting them into shape.
Make the bases. I took bits of scrap plywood from my River project, and cut them into irregular shapes with a hand-held fret saw. If you had a thin blade for a small bandsaw, that would work brilliantly as well, but I don't have a bandsaw yet.
Glue the foam to the plywood using Tacky Glue (a thickened PVA, like Elmer's White Glue, available at craft stores in the US). Let that dry.
Paint the plywood base. I painted mine with Burnt Sienna craft paints, as they are destined for Mars' red soil. You may want to try a different color for other planetary surfaces.
Paint the crystals. I chose green shades, to stand out better against the reddish soil of Mars. Again, you may choose your own colors. I painted the whole crystal in Vallejo Deep Green, then painted ridges and edges in Vallejo Intermediate Green, and finally did a thin line of Vallejo Light Green along the edges and drybrushed a bit in the center of the facets for a light effect.
Flock the base. Last, I painted some thinned down PVA glue on the bases and covered the bases with the reddish-brown sand I am using for Martian terrain. At this point, I also added a few small details around the crystals, like gravel and undergrowth.
I am going to use a similar technique, but different colors and shapes, for some "unobtainite ore" on Venus soon. I'll post photos when I am done.
If you want to see more photos, check the photobucket link in the margin for wargames terrain.