Ah ok, I think we're thinking of the same thing then.
Could be various impurities or the shape of it.
-e
Actually, just as far as sensitivity goes, just tie it to purity. Pure Beryllium would be a mega-sponge, though it wouldn't have much capacity what with not being in a crystal. So just get Beryl with further Beryllium impurities to get highly-sensitive absorption with some capacity to it.
Heh, fun but hard to come by. Even with a very large crystal, depending on how MILF replenishes, they'd have likely died off long ago outside of dead zones. Once they're found, you could probably transport them by putting'm in a resist-magic box.
hehe, stupid-large wizard-crystals could be responsible for dead patches of their own, thousands of years of MILF only a drop in the olympic swimming pool.
Edited my last IC post with more description.
Here's an image to give a good impression of the shield- though it's an oval rather than a circle.
The anchors for the gems (black snakes) are true meteoric iron, and they extend clear through the shield when they're deployed, (about an inch deep, the gem protruding another half-inch from the surface of the shield). They lack bottoms to accommodate longer crystals, but do have a bottleneck to anchor the gem arrays. The bottleneck allows gems up to 2 inches in width, which at 1.5" long would be worth ~550 middling spells. What I've got is more like 1.3 inch
3, which is more like a dozen.
The central gem is 1.2" wide & worth about 1600. But by itself it'll only decrease spell effects. The whole series is important for good protection.