(read how to identify your stamp below)
You have the 2c Jackson from the years 1870-1873. It is quite common.
If the color of your stamp is closest to the brown of the stamp on the right, click here.
If the color of your stamp is closest to thered-brown of the stamp on the left you should look for an embossed pattern on the back of the stamp, called a grill, an example is shown below.
If the left stamp has a grill embossed on the stamp (shown below), click here.
If the left stamp has NO grill embossed on the stamp click here.
This stamp was reprinted in 1875 and it can be viewed by clicking on the numbers 167-177. These are all accounted for, so you will not own this.