In your case, according to your opinion,
as per current market price of ₹58,353.00, you should price your GPU at 58353*0.7=₹40,847.1.
Although I agree with some of your opinion regarding you having spent your hard-earned money on your GPU,
Technically, mining does not harm your GPU. I am strictly against mining, never done that in my life, probably never will. But time and time again people have come to conclusion that if mining was done in a clean environment and proper care was taken, it does not harm the GPU core any more than gaming does. High-res high quality gaming keeps GPU pinned at 99-100% and mining is generally done at lower power. Memory chips are different thing altogether.
In my opinion, if the GPU looks clean with no burning smell, has proper box and bill and no issues with warranty, if you take care of the GPU afterwards, mining used GPUs are pretty sweet deal as a gamer.
But with so many caveats, people will prefer getting one new for the fresh smell of new hardware and peace of mind.