Gneaea Seia Herennia Sallustia Barbia Orbiana is best known as the wife of Severus Alexander.  Possible one of three wives that he had.    Little is known of Orbiana.   She was from a distinguished family, the daughter of Senator Seius Sallustius Varius Marcinus.   She was married to Severus Alexander around 225 when he was about 16.   She must have initially met with the favor of Severus Alexander's mother Mamaea but this didn't last long.  Orbiana had too much influence with Severus Alexander and this led to direct confrontation with Mamaea.  Whether real or not, a plot was found to be led by Orbiana's father to turn the praetorian guards against Severus Alexander and put himself in power.  The marriage between Severus Alexander and Orbiana was dissolved at Mamaea's insistence in 227 AD.   Shortly later, Sallustius was executed and Orbiana was banished to North Africa.  Poor Orbiana.   It doesn't pay to get between a mother and her son. 

I will now highlight coins of Orbiana.   They are all scarce and many rare.

Orichalcum sestertius, RIC 655, VM -2/1, S 2302, F, 21.4g, 31.1mm, Rome mint, 225-227 A.D.; obverse SALL BARBIA ORBIANA AVG, diademed and draped bust right, reverse CONCORDIA AVGVSTORVM S C, Concordia seated left holding patera and double cornucopia.

Denarius of Orbiana, RSC 1, BMC 287 - 90, RIC 319.  Obv.  SALL BARBIA AVG, her diademed bust draped right.  Rev. CONCORDIA AVGG, Concordia seated left on throne, holding patera and double cornucopiae.

Here are two modern copies of the same coin.  Notice the differences.

Here's another modern copy.  This is a sestertius copy of BMC 300, RIC 657.  This coin is AE31 and 16.9 grams.