Had several fail like this myself, even when they've been installed and left alone it just randomly happens. The G12 capped single ended lamps are a lot more robust than these.

But in G12, HPS aren't available and coloured MH lamps are even more rare than in R7s 70W.

And why lamp base of R7s lamps, are made from a fragile ceramic?

I have selected some special weak lamp holders to mess with RX7s lamps, to avoid these mishaps, after having managed to crack two rather rare violet gallium metal halides in a sadistic ) lampholder in one of my luminaires. You probably can still find some green MH lamps on Aliexpress, if not I can probably dig up some intersiting specimens here in Kaszkhstan for you.

That's a shame!

I need a 70W R7s, and these aren't available anywhere except the British wholesalers. I found one in the UK eBay, but the picture displayed a lamp with a heat reflective coatings.