Zanotta coffee table identification wanted  

Help wanted with this coffee table. It has a diameter of 59.5 cm (23.5"). It is made out of concave shaped steel covered with leather on top and bottom. Legs are stainless steel. Six socket head screws keep the legs together It has a beautiful decoration and signed on the bottom. Tried to figure out the designer but to no avail.

Would anyone know how old this table is? And who the designer is of the model and the designer of the decoration? Also the leather is black on the bottom. It appears to black on top as well. However when it is rubbed it gives a blue colour.

I wonder if the original colour was black or blue. Also tips on how to restore the surface would be appreciated.

Thanks!