First you will need to hang onto the sprues from the little green rods that come with your Necron Warriors, Necron Destroyer and Necron Monolith kits. This is the essential component for creating the crystals seen on the bases in this article. All you'll need beyond that are some hobby clippers and textured paint.
The sprue to be used is shown in the photo below. After you've removed the little green rods for use on your models you are left with quite a bit of transparent green plastic. This will be used to make crystals for your bases.
Next, cut some pieces off of the sprue at odd irregular angles as shown in the next photo. The angular nature of the cut pieces will catch some light once they are on the model bases. I not only used the larger chunks I deliberately cut I also used some of the smaller flakes and bits that were generated in the cutting process.
![](https://2.bp.blogspot.com/_3XUQ_7wPKt4/SiKpa-v3GdI/AAAAAAAAAkg/4c82wmLcm_0/s200/Black+Lava%5B7%5D.jpg)
After the paint is completely stiff and dry carefully dry-brush it with some grey to give it a highlight. Be careful not to get the grey paint on the crystals or the Necron model.
Your finished base will look something like the one below. Of course, you can use more or less crystals to your taste or make them larger or smaller as you desire. You could also use colors on your texture other than just black and grey to suit your taste so long as they don't clash with the model or the green crystals. I tried to have some noticeably larger green chunks with tiny irregular sized bits and flecks here and there as I wanted a naturalistic look suggesting the crystals were growing.
This is how the bases look on my finished Necron Canoptek Wraith unit. When I find some time I was planning to use this method on the flying stands in my Necron army as well.
Judging by the positive reaction I've had to this basing method from passersby at my local GW Bowie Battle Bunker I believe I've hit on something fun and evocative using bits of clear green sprue this way. It's extra fun finding a cool use for things that would otherwise end up in the recycle bin.