Hi James,

Thank you for contacting Mearto with your appraisal inquiry.
According to this website (https://findyourstampsvalue.com/rarest-stamps/most-valuable-italian-stamps), what makes one version of this stamp particularly rare are the white blocks in the corners with dot - yours does not have those. I can't find the number of these printed but it would appear to still be relatively valuable; without a comparable, I've valued conservatively.
Based on the photos and information provided, and subject to examination, this is:

A circa 1874 Italian "Un Centesimo" (One Cent) Olive Green postage stamp
1 by 7/8 inch
CONDITION: cancelled, loss to one corner, perforation losses, ungraded
$400-600*
*represents a fair-market value for auction purposes; retail or asking price may vary.

Please let us know if you have additional items to appraise, and thank you again for using Mearto.