From the Baykos Glassworks.

The site of the Topkapi museum explains better than my notes from the Bursa museum: “The production of glass in Istanbul began with the Mevlevi dervish Mehmet Dede, who was sent to Italy by Sultan Selim III (r. 1789–1807) to learn glassmaking techniques; having studied these techniques in Venice, Mehmet Dede returned to Istanbul, where he began making glass pieces that, though at first resembling the glass products of Venice, soon began to show a distinct Istanbul style. In the glass workshops that were founded in Beykoz and that became synonymous with Istanbul glassmaking from the 19th century onwards, three different techniques were used: çeşm-i bülbül (“eye of the nightingale”) glass; opaline glass; and crystal and transparent glass. Of these, it is çeşm-i bülbül glass—in which colored sticks of glass are bound with the body of the glass piece and then twisted—that is most identified with Beykoz glass.”

On the picture: Glass walking sticks.
Bastonculuk (= the making of walking sticks) is a well established trade since Ottoman times.
In general different kinds of hardwood were (and are still) used, and sometimes more exclusive materials.

Correspondent: J.M.Criel, Antwerpen.
Source: Website of ‘sanatpenceresi.com’ .