Is there a 1946 Calcutta version?

This listing has a 1947 with no mintmark date, but none for 1946. Someone recently gave me this coin, is it likely the mintmark has eroded, or the coin itself is a fake?

It might be there, it's about the right place, although it looks more like a diamond:

It is a diamond.

rsirian1

It is a diamond.

It looks indeed like a diamond. And this was my first thought:

But Numista and Krause say the mint mark for Bombay coins from British India is a dot and not a diamond, so I was searching for a dot and the darker area within the rombus could be, with some fantasy, a dot. But the first impression was a diamond.

Thanks both, wouldn't be the first heavily eroded Indian coin mintmark I've seen. Agree it's vaguely more a diamond than a dot.

Compare to the ¼ Rupee. N#6555 A diamond on the Numista page.  SCWC same as the ½ Rupee.

Then we have to change the dots here (N#8239) into diamonds.

Yes, apparently it was already done once. https://en.numista.com/forum/topic78308.html

Or maybe they just added the diamond in the Comments. Originally it only said dots. From 2016:

Also, delete the Calcutta Mint year line which was probably added when someone found a worn off diamond (or dot) coin.