The Witcher felt it. The magic that was surrounding him. It was everywhere, yet he could not see it source. Only dead wasteland around, no signs of life. He made few steppes and felt like his medallion start trembles. Little amulet shaped into wolf head warned him about something he could not see nor hear. Lurking, waiting for Witcher to make bad move. Monster hunter grabbed his silver sword and pulled it out, he felt that battle is imminent and had to be ready for it. One step forward, second, yet nothing happened. And before he was able to make another step, a giant stone hand grabbed his foot trying to pull it under the ground. Warrior made a neat cut and shattered the hand, releasing his leg from powerful grip, and jumped back to avoid monster that emerged right in front of him. A giant, almost 3 meters tall stone beast stood in front of surprised Witcher.
"So it was you." He said making quick dodge to avoid incoming strike." A Golem. I haven't seen your kind for quite a long time now. The question is..." Witcher had to jump back as beast almost crushed him under its giant hand.
"Who made you? Where is the wizard that was stupid enough to create you and leave here?"
Golem growled deeply and continued its assault. One strike after another, Golem was getting slower, weaker, while Witcher became fast like a wind. Wind that was able to cut where it hurt the most, making the beast fall on its knees. When Withcer spotted his chance to deliver a killing blow. He jumped on living stone back and stabbed its enemy in its neck, trying to rip off its head. Before it happened beast grabbed monster slayer by his vest and pulled. Yet the only thing it managed to get was Witcher medallion, that ended up crushed in Golem mighty grip. Moment after that silver sword moved deeper into beast neck and finally cut it away, instantly killing the stone creature. Giant body fell on the ground and shattered into hundred pieces.
Victory was achieved yet Witcher lost his precious amulet. But before he left the field of battle, he spotted that inside Golem shattered body, rests small piece of special metal. Ore from which his amulet was made. He took it without second though, and went to the closest city, where his friend lived. The best metallurgist and jewel-crafter in whole kingdom. With his help Witcher was able to make a new medallion, that was even better then the previous one. But the piece of metal was big enough to make not only one amulet, but 18 in total. Witcher took only one, leaving the rest in the hands of his friend, believing that he will find for them good owners.
And thats how you got those 17 Medallions
Sorry for my Bad English, I just hope this little story sounds not that bad. And Im sorry if some things are wrong in this story. I don't know from where Witchers are getting their medallions so I had to come up with something that could be possible.
And yes I would love to have such amulet.