Turkey Revenue Stamp

I need some help identifying this stamp. I believe it to be a Turkey postal tax stamp issued in 1925. Scott catalogue starts their postal tax section in 1928. If anyone could give me a catalogue number and catalogue value I would really appreciate it. I'm not concerned with a scott number, michels or any of the other major catalogues will do. Thank you.

Please post an image of the rear of the stamp,
I'd like to see the PERFIN

This is a Turkish General Revenue Stamp, 5 Piastres paras Violet

We both have an unlisted colour variety "Violet Blue"
McDonald lists only Reddish Violet

Correction: My 1 Piastre is listed in Violet Blue, your 5pi is not listed in that colour.

1925
Perf 10.5, 12, 12x13.25, 13.25, 13.25x12,
22.5 x 29.5mm
Unwmkd

McDonald Page 22.
24 Revenues listed in set. 10 paras to 90 Piastres.

Perfins are two "1"s conected at the base.

Would this then be a color error since it is not listed?

And would you happen to have an estimate of its' catalogue value if it were not a color error?

Thanks, you have been a great help so far.

Thank you
1. I doubt a Perfin, looks like a municipal revenue puncture,
perhaps from a document, however that is only speculation.
Puncture 11
Only perfin I recall from Turkiye is BIO, and WBV (Bank of Austria)
Banque Imperial Ottomanes.
There are 55 Known Perfins

Again speculation, colour is not an error, just not seen by McDonald at that time for listing, the fact that others exist in this hue, suggests a different print run.

McDonald lists this 5pi at $1 in 1998
I shouldn't think it would have increased by any margin, esp as a "general revenue"
20paras to 30 piastres are $1-$3
Top currency value cv $30

Thank you for your help. I really appreciate it.