what is Goldschmidtite?

A new, curious mineral has been discovered inside a diamond unearthed from a mine in South Africa.
The mineral has been named goldschmidtite, after Victor Moritz Goldschmidt, the Norwegian scientist acknowledged as the founder of modern geochemistry.
Goldschmidtite has an unusual chemical signature for a mineral from Earth’s mantle
While the mantle is dominated by elements such as magnesium and iron, goldschmidtite has high concentrations of niobium, potassium and the rare earth elements lanthanum and cerium.