Obsidian glass in a medieval or fantasy city: where it can be made, what it needs

Where a city can make obsidian glass, and what it lacks elsewhere.

What it may lack

• needs lava baths (a fantasy option)

Orders of magnitude for play: sourced figures and Hearth estimates together. Every source, and every figure still waiting for one, is listed in the builder under Sources.

Open the city builder — MGS Toolbox