The historic times show a continual decline in the quality of the stone used. In the Ist dynasty the hard stones decreased, and the softer slate and alabaster were more common. In the pyramid age only diorite continued in use among the hard materials, and that but rarely compared to soft stones; while in the XIIth and XVIIIth dynasties, beyond an occasional vase of obsidian or serpentine, nothing is seen but the soft alabaster. The form J belongs to the VIth dynasty. K is a type which descends from the Ist dynasty, but in this form wide at the top belongs to the XIIth, after which it disappears. L and M are of the XVIIIth dynasty. Amulets of fine stone were used from prehistoric days onwards. Of the early ones, the bull’s head is the commonest, made of carnelian, haematite, or glazed quartz. The fly is made of slate, lazuli, and serpentine in prehistoric times, and of gold in historic jewellery. The hawk is found of glazed quartz and limestone, the serpent of lazuli and limestone; the crocodile, the frog, the claw, the spear-head are all found in prehistoric use. In the Old Kingdom, small amulets of carnelian or ivory were usual; the forms are the hand, the fist, the eye, lion, jackal-head, frog, and bee. In the Middle Kingdom the more usual material was silver or electrum. The New Kingdom used amulets but little; the great profusion comes from the mummies of the Saite time, when dozens may be found on one body. The great variety of forms and materials would require a volume to explain them. Beads were used from prehistoric times. The hard stones were cut then--quartz, amethyst, agate, carnelian, turquoise, lazuli, haematite, serpentine, as well as glazes on quartz and on paste. Glazed pottery beads became the more usual in historic times; glass beads were made from the XVIIIth dynasty onward, and hardly any other material was used in Roman times. There are hundreds of varieties known, and an accurate knowledge of their dates is essential in excavating.