Chalcedony

218NA
Chalcedony necklace
2-3 century AD
Roman or Parthian

Composed of 9 large compressed sherical ancient chalcedony beads, all graduated in size. Interspersed with ten modern Turk's head knots.
Each bead has a large bi-conical hole. 

Max diameter of the largest bead: 32 mm
Height: 22 mm
Necklace is 20" ( 50.8 cm) long

For similar beads see:

-Alexeeva E.M. Antichniye busi severnogo prichernomoriya, Academy of Science, Moscow, 1978, table 37: 14

-Christie's, New York, 5 December 2001, lot 98

-Christie's, New York, 6 December 2007, lot 434