If it is a circulation mark then you have a one of a kind item here! It is a die chip on the post then you have one of many dimes minted from that die with a similar, partially-filled mintmark. Unfortunately, in both cases it is just worth face value.
"If you climb a good tree, you get a push."
-----Ghanaian proverb
"The danger we all now face is distinguishing between what is authentic and what is performed."
-----King Adz