Antique Islamic glass trade beads - Zanzibar

A nice collection of antique glass beads of different periods in time and places of origin.
The larger light blue glass beads are of Syrian origin and were produced in the 16-17th century, predating European imports. Mostly exported to Islamic counties like North-Africa and the islamic East-African coast. Dim. 4-7 mm.
The much smaller glass beads with the brick-red /yellow/green and blue colours are of indian origin. Very visible in the very long string of mixed colours. These bead imports preceded the Portuguese beads. Mostly from the 15th-16th cent.
Dimensions; 3-6mm. These beads were found sifting through the sands near the harbour of the island of Zanzibar.
Four of the strings have been made into short necklaces, with a lock. Apprx. 25cm. long.
Collected on the island of Zanzibar in the early 20th Cent.