Constantius II AE3. 

Obv: DN CONSTAN-TIVS PF AVG, pearl diademed, draped & cuirassed bust right 
Rev: FEL TEMP REPARATIO, radiate phoenix standing right on globe
Mintmark: CONSA

RIC VIII Constantinople 93 var, rated R4/R5. 

Only one other is known with this mintmark (in Kelly Zane's collection, US). 
The rarity and difference lies in the fact that the mintmark is not followed by a star and is unrecorded in RIC, Cohen etc.

Contributed by Dane for George Clegg (biggyg2), April, 2008.