Any clue about this coin? [solved]

There are a store selling this coin online for less than 3 euro, I know the salesman have no clue about this coin (as do I), but I realized that if this coin worth anything, I'm willing to buy among others  I'm currently negotiating.

I searched for Indian coins and mughal coins, but that small worm letters means tottally nothing to me, I have absolutely no idea even for what to search.

So the question is, what is this coin, and does that worth anything?

Thanks for any reply.

The first picture is upside down, the second sideways.
It should be like this:



It's the 1 pice from British India - Bengal Presidency - Calcutta Mint.

There are several different types, depending on the year. They all have the "frozen" regnal year 37, this means that no matter which year the coin is effectively issued, the regnal year was in all these cases 37.
So there are several possibilities, detectable by weight:

C# 706 (1795) 11.60 gr.
C# 706a (1796) reduced weight, 8.7 gr., large and small flans.
C# 706b (1809) reduced weight, 6.54 gr.
C# 706c (1817) reduced weight, 6.46 gr.

There is also C# 706d (1829) en C# 706e (1831). Yours is certainly not C# 706e because that coin has a slighter different reverse.

I don't know what the difference is between  the C# 706c en C# 706d. They should have the same weight.

Source: The Standard Guide to South Asian Coins and Paper Money since 1556 AD, first edition.

https://en.numista.com/catalogue/pieces50373.html
https://en.numista.com/catalogue/pieces22954.html

Wow! Thank you for the enlightnement, I will get this coin anyway. Shame on me to paste upside down, but now I know what it is.
Essor, you are amazing!

Meanwhile I also found the matching KM# numbers and some values:

C#706 = KM#52
C#706a = KM#53
C#706b = KM#54 althoug Craig says the weight is 6.54 gr. and KM says its 6.23 gr.:



C#706c = KM#55:



C#706d = KM#56:



C#706e = KM#57 with a weight of 6.13 gr. according to KM:



In the red circle you can see that this is not your coin. Here the three diamonds are on the same hight as the other symbols, on all the other coins the three diamonds are higher.

Essor Proof, you are the man. Thank you for your research and the awesome identification and valuation!

I see it is a cheap coin in this condition, anyway it is special to me now.