Electrically conductive gem-like compounds
From apm
A subgroup of diamondoid compounds.
Conductive compounds in thicker layers do not let light pass but do reflect it instead.
See wikipedia: plasma frequency
- hematite, magnetite, pyrite, ...
- members of the spinell mineral group with metallic conductivity
- some copper and lead sulfide compounds
- in an AP pattern doped silicon and diamond (rather low level metamaterials than compounds)
Often high level diamondoid metamaterial might be a batter choice like crosshatched conductive nanotubes. One direction only would let through polarized light.
