Fluorite Cars

According to a dream I just had, cars would be much safer if fluorite, more specifically blue john, was used with them in a way that was not specified. Here it is.

All possible components of the car should be made of fluorite, mainly mined and sculpted, and of artificially synthesised calcium fluoride. Since it has a density only 40% that of steel, such a vehicle would be lighter than quite a few other vehicles of similar size and therefore me more energy-efficient, although less so than a plastic vehicle.. It would also be a lot more brittle than steel, so it probably should go quite slowly. On the other hand, on impact it would fracture rather than bend, making it somewhat safer, and since it's not as hard as apatite, the crash victim could gnaw her way out with her teeth given enough time. The lower density of the material would also reduce the risk of crush syndrome and various other injuries, and since bones are also harder than fluorite, the risk of fracture from penetrating injuries would also be lower.

The windows could also be made of fluorite, which is widely used in optics mainly because chromatic aberration is not as pronounced through it, but also because ultraviolet can penetrate it, meaning that it would be easier to get vitamin D while driving. Also, headlights able to emit ultraviolet light would cause certain objects ahead of the vehicle in darkness to fluoresce.

I imagine the engine to be electric since the melting point of the material seems too low for combustion to be used.

PTFE could be used for various parts of the vehicle usually made of plastic which would make surfaces easier to clean. The tyres, however, should not be made of it for obvious reasons.

The main problem I can envisage is that sulphuric acid in rain would generate hydrogen fluoride, which I suggest would be alleviated by merely painting the exterior.