Mexico underwent monetary reform in 1992, with one new peso equal to 1,000 old pesos. This new 20 peso coin is denominated as "N$ 20" (N for "new"). After 1995, the "new" designation was dropped. I was quite surprised to see actual silver being used in a common coin at the end of the 20th century, but here it is.
All coin images in Daniel's Coin Zoo are from my personal collection. I collect, research, and personally photograph every coin displayed on this site. PLEASE do not take my images without permission. If you would like to use any coin image you see, just ask me. Thank you.