Well, given that there was meant to be a fourth Disciple of the Land class named 'Shepherd' available to players in the original version of FFXIV, only for the class to be dropped and never touched on again, it's clear that besides the guilds that are available gameplay wise, there is bound to be trades that involve manufacturing other items or materials not covered by the existing classes (like brickmaking, stoneworking/masonry, and yes, glassblowing would all probably have their own specialized disciplines, but the game does not go into that).

And speaking of glassblowing, besides the more mundane use of glass in Eorzea like windows, bottles for medicines and beverages and lamps, another more esoteric use for glass that even features in gameplay is guildleves, specifically the leve plates, are made of stained glass in a metal frame, so there would need to be some way of making said glass... unless it's just another thing handled by the GSM's Guild (in a way glass can sort of be considered 'stone' I guess), as besides jewellery they also make clockwork gears and movements used in mammet brains (which are basically clockwork computers), so glassmaking would easily fit too.

But that's just my own musings so your guess is as good as mine.