formula for carbon dating half life - Optical dating of granite stone surfaces
Their shells were traded near the Pacific Ocean and then trekked by foot far inland, to the deserts and high plateaus of the Southwest in pre-Columbian times.There the Anasazi and other Native American artisans cut abalone shell into thin disk beads and geometric pendants, and crafted inlaid and mosaic ornaments combining shell with other precious materials, such as jet and turquoise.See Also: Mother-of-Pearl Pearls Shell Beads This Hausa term for bauxite beads is widely used by West Africa traders.
In addition, Afghanistan was a source of etched carnelians of various types and even some shell beads.
The beads shown in these images range in age from the Neolithic Period to Islamic times and measure from 0.8 to 6.7 cm long.
AB finish is widely used on seed beads and bugles; Czech molded glass beads, both smooth and faceted; plastic plain and fancy shapes; and cut glass crystals.
See Also: Fumed Glass Iris Finish Swarovski Crystal Mother-of-pearl from the nacreous lining of abalone shells has been used to make beads and ornaments since prehistoric times.
Afghanistan was, however, the source of the tabular and lenticular beads, which showcase the beauty of the stones, many of which are translucent.