I'd not put it past the Turkish trading routes to have mammoth access to areas having such materials. The latter can be found just floating around.
As I know from experience.
(Topic off)
Anecdotal evidence.
Our ship was heading north from LA to north of Point Barrow, with a stop in Juneau on the way. A keen seaman spotted an object ahead that turned out to be the bloated body of Wally the Walrus**, the Captain stopped the ship, sent the ready boat & crew to retrieve the highly visible large tusks from the bloated corpse (they used a saw).
I watched from a distance of about 100 ft. from the main deck and the smell was overpowering. The crew involved at the corpse was not amused. Wally floated off into history, His tusks were boiled and dis-infected by the ship's doctor - we had a real one on that trip, from the USPHS - and the ships carpenter on orders mounted them on a wooden plaque. The CO presented the still smelly thing to the Governor when we hit Juneau. I'd bet the governor gave it to an aid to throw in the trash
He was always lobbying support for his promotion to Admiral, which needed Congressional approval. He did not make it, thank Heaven, as he was universally hated and a right moron, and we couldn't figure out how he ever made Captain. He had me (I was the Morale officer, a collateral duty I passed to a more junior officer as fast as possible) buy a pool table for the crews use out of Morale funds. In spite of the fact it was impossible to keep level on a ship. Should never have been in command of anything larger than a bathtub*. The XO was very good and actually ran things, thankfully.
* - The Captain's Stateroom actually did have a bathtub! Obviously unusable at sea, It could be used in port as long as the ship was fairly level - unlike the pool table.
We now return you to your regularly scheduled discussion.
(Topic on)
**- Wally in better days.