Serendibite

Serendibite is one of the rarest and one of the most chemically complex gemstones in the world being made of calcium, sodium, aluminum, magnesium, iron, silicon, boron, and oxygen! With the ability to substitute many elements meaning one element can be swapped out for another or both exist at the same time. Complex gemstones rarely exist because getting so many elements of different atomic sizes to fit together in a stable crystal structure without others being rejected is extraordinarily difficult

The best part is despite looking pitch black its a complete illusion, it has heavy concetrations of fe2 nad Fe3 iron so depending on which type its eithe a blue-green or yellow but its so heavily concentrated it appears black! This is because those varieties of iron have vacancy spots on the atomic level that temporarily absorb energy, in this case, light!

Hardness: 6.5 – 8
Composition: (Ca,NA)₂(Mg,Fe²⁺, Al)₆(Si, Al, B)₆O₂₀