3 Cent Embossed Stamp

Hi Folks, I'm new to this forum and collecting in general; but I have a question about an envelope and embossed three cent green Washington stamp that I just acquired. The letter is in great condition, has never been used and the flap opens with glue still visible. I don't know if it's purpose was to actually send mail, as the front of the envelope has a large imprint of the Babcock Manufacturing Co. Chicago Illinois on it. Any idea of a production date or possible value?

We need a closer up scan of the stamp itself. Nice Ad cover! It is fairly common to find ad covers un-cancelled as they preprinted these in batches for customer replies or payments.

Does that help?

Agreed we need a close up scan of the indicia to accurately identify the envelope, but the series of envelopes in which this would be a part was generally in use from 1874-1886.

The Babcock Manufacturing Company was out of business by 1897 (as their successor, the Consolidated Fire Extinguisher Company is advertised in the piece below):

Thats Great, I had a feeling it would be late 1800's. I posted a blown up image of the stamp which is quite grainy, but i'll try to get a clean version to post later.
Thanks

It appears to be on amber paper, which makes it Scott U83, a common entire. If the paper is white, not amber, than it is U82, also common. It is "unused" (not "mint" but not cancelled/postmarked).