The goddess Maat personified justice, truth and proper world order. She is portrayed in amulets like this one as a seated or squatting woman with a single feather (the hieroglyph for her name) on her head. This example is made of mottled lapis lazuli. There is a ring on the back for suspension.
From Giza. 1927: excavated by the Harvard University–Boston Museum of Fine Arts Expedition; assigned to the MFA in the division of finds by the government of Egypt.
Harvard University—Boston Museum of Fine Arts Expedition