Asbestos came into its own during the industrial revolution, when engineers harnessed its fire-proof, heat-resisting and insulating properties in their new steam-driven factories.
In addition to tourism the city has mines of niobium (columbium) used in jet engine components, rocket sub-assemblies, and heat-resisting and combustion equipment.
Great progress has taken place over the years until now we have hard glass, soft glass, heat-resisting glass, thick glass, thin glass, decorative glass and countless other varieties.
