Have an old nail that I have not seen before. It has a button type dome top, shaft is made different

[jallml]

The nail is square as it goes up the shaft then is seems to be hammered to flatten out at the top. The head is round to oval and not uniform. There is a dome in the center lined up directly over the shaft. Does this nail have a special purpose and name? thanks for any help

[rogersrr]

Try a search for a rose head hand forged deck spike..

[teresaspeedo]

That is a cut nail made between 1790-1830 but found in homes built up to 1880 especially in areas of the country built out late such as our 1880 home here in western Massachusetts.  I have examples of this very nail but have yet to find a reason for the reverse dimple.  See here: http://www.journalofantiques.com/Aug02/businessaug02.htm