An antiquary is someone who studies antiquities. It’s an older and more scholarly word than antiques dealer, carrying a sense of expertise rather than commerce, and the learned societies using the title date back centuries.
That scholarly register is the asset. The antiques trade has a credibility problem at the low end and a knowledge premium at the high end, and a name that sounds like expertise rather than retail positions a business at the right end of that. It fits a dealer, an appraisal service, a research resource, a collector community, or a publication.
The word also covers books, manuscripts, and coins, where the antiquarian trade is a serious business with its own fairs and specialists.
Nine letters, four syllables, one spelling, and a single dictionary word with no competing commercial owner. The .net reads fine for a network of dealers or a reference platform.
The name is listed for sale. Offers considered.