<Tr> <Th_colspan="2"> Feldspar </Th> </Tr> <Tr> <Td_colspan="2"> Feldspar crystal (18 × 21 × 8.5 cm) from Jequitinhonha valley, Minas Gerais, southeastern Brazil </Td> </Tr> <Tr> <Th_colspan="2"> General </Th> </Tr> <Tr> <Th> </Th> <Td> Tectosilicate </Td> </Tr>

What are the 20 minerals that make up earth crust called