I thought this might be Septimius Severus until I saw the photo, must need new glasses. Can anyone give me a hint to who the emperor is. I am stumped. Edit: Forgot the size: 18mm 3.24g
Looks kinda like Hadrian with Aeqvitas reverse; however, if so, it is a fouree of a denarius similar to RIC 228
Doug you are a star! My first thought was Septimius but he seems strangly lacking in the beard department. A Limes seems right. Septimius Severus Limes AE denarius. Military mint on the Danube border. Obv: L SEPT SEV AVG IMP XI PART MAX, Laureate head right. Rev: AEQVITATI AVGG, Aequitas standing left, holding scales and cornucopiae. AD 198-200 Limes version of RIC IV-i, 122c; Cohen 21; Sear 6259 var (obv legend).
I'm sure Doug is correct, but, man, that profile does not look like Sep Sev. Here is the coin I was looking at PP: http://www.wildwinds.com/coins/ric/hadrian/RIC_0228_2.jpg
The photo show scratches from cleaning in the right side reverse field, on both sides of the P on obverse left LSEP and, most importantly, across the chin which in effect shaved poor old Septimius. I may be imagining things a bit but wiggle the coin under the light and see if you find diagonal lines that might have lessened the beard.
I have had a wiggle. Yes, possibly some sort of shadow may be there. Someone had a real go with something sharp before I got it.