Short answers, pulled from the story.
Scarabs served as amulets, impression seals, personal jewelry, administrative seals, and funerary objects. They were also produced for political and diplomatic purposes, with commemorative scarabs sent as royal gifts to advertise and celebrate the achievements of pharaohs.
A heart scarab is a funerary amulet, typically 4 cm to 12 cm long, made from dark green or black stone and placed around the neck of a mummy. Its base was inscribed with hieroglyphs from spell 30B of the Book of the Dead, commanding the heart not to testify against the deceased during the weighing-of-the-heart judgment in the underworld.
Most scarabs were carved from steatite, a soft stone that hardens into enstatite when fired, or molded from Egyptian faience, a sintered-quartz ceramic. Hardstone scarabs were most often cut from green jasper, amethyst, or carnelian. Scarabs were typically glazed blue or green before firing.
Amenhotep III was the immediate predecessor of Akhenaten. He is famed for having large commemorative scarabs, mostly 3.5 cm to 10 cm long, made from steatite. More than 200 survive today, inscribed with accounts of five key events from his reign, each mentioning his queen Tiye, and believed to have been sent out as royal gifts supporting Egyptian diplomatic activities.
Thutmose III, who ruled from 1504 to 1450 BC, was worshipped as a god after his death and his cult appears to have persisted for centuries. His throne name Men Kheper Re came to be regarded as a protective charm in itself, and scarabs bearing it were produced long after his reign, sometimes by carvers who may not have understood the inscription's meaning.
Phoenician seal engravers adopted the scarab during the period of the Achaemenid Empire, from the later sixth century BC to the mid-fourth century BC. The city of Tharros on Sardinia became a major production center, and Greek and Phoenician merchants transported scarabs to the Etruscans in the fifth century BC, where they were most popular in Vulci and Tarquinia.