Actually this will help to increase market.
Lets see... 60-70 people in game have top jewelry, other 600 not... and have almost no chance to do.
Also there is question about time... if you need something fast.. and you know its on market you can go and buy it.
If you worry about external income of silver, that is actually not problem. I spend so much of silver, I will easily transfer working power to other needs. Also Jewelry hq will be needed by everybody... At this moment I see no chance for simple person to buy monocle for linen or mussels...
They just couldn't put that much in inventory, so there is needed something between.
I don't think silver coins gives bad ranging in price. This market susposed to be HQ stuff, impossible to reach for 90% of hearthlings.
So silver coin is just good for it

We can use gold coin of course... if somebody have 40-50 bars of gold to put into marked changing it to silver or other stuff to start market working.