Final answer:
Muscovite and biotite are examples of tetrahedral sheets in silicate minerals. They have different appearances and properties, but both belong to the mica group.
Step-by-step explanation:
Two examples of tetrahedral sheets in silicate minerals are muscovite and biotite. These minerals are members of the mica group and have a layered structure composed of thin layers of mica. Muscovite has a wavy appearance with a sheen, while biotite has thicker layers and a darker color.