Yes. I paid $70 US to get a good one. It runs at a very high speed. It is battery powered and has many ends. It uses the 18650 lithium ion battery (also used to make power packs for laptops, power tools, even bikes and cars). I got this one on Ebay, it was listed as "Electric Mini Chargeable Engraving Pen Machine For Carving Grinding Metalworking". It is good quality and came with many unexpected accessories. It easily ground through the glaze and into the porcelain far enough to remove the speck. Then I just needed to fill up the hole with glaze and refire. This could also be used to remove burrs and nicks that might make a piece unsaleable. Can you engrave (e.g. text) into a glaze or porcelain? No. Even though there are heads intended to do this, the spinning motion gives the tool a mind-of-its-own about where it wants to go. And it hops. A lettering template might help but it would still be very difficult to get a deep enough scratch into the surface to be visible.
Specking is a fault in fired ceramic ware where speckles of ion bearing contaminants are visible and mar the appearance of the surface.