Great coin and a nice writeup jsk. With your permission I would like this to be the leadoff for her thread in the Women of Rome series. Let me know if that's okay with you. I am going to add my bit here, which we can ditch if you don't want to do this.
For historical background here is a piece CNG wrote up for one of their coins for her:
One of Elagabalus' greatest offenses was his marriage in 220 to the Vestal virgin, Aquilia Severa, following his repudiation of his first wife, Julia Paula. The Vestals were under a solemn vow of chastity, but Elagabalus defended his behavior in a letter to the Senate arguing that a child begotten of the high priest of Ela-Gabal by a priestess of Vesta could be little short of divine (he, however, betrayed his true motive when he added that he was in love with her). She was, it seems, the one woman able to overcome his distaste for the opposite sex. But the Roman historian Dio spoke for established opinion when he described the violation of a Vestal as an act "for which he [Elagabalus] ought to have been publicly scourged, thrown into jail and put to death." The indignation aroused was such that Elagabalus was forced to yield and Aquilia had to retire after only a brief period as empress.
For a more extensive historical background on her obligations as a Vestal Virgin see http://goccf.com/t/285580
Her silver coins date mainly to 220 A.D. with some coming later at intervals as well. There is only one obverse inscription for her IVLIA AQUILIA SEVERA AVG. Hair in waves running transversely downwards and turned up in queue and small bun at back.
This is backed by one of three reverse inscriptions on a total of four types:
1. the common CONCORDIA featuring Concordia draped standing front with head l. holding a patera in her r. hand over a sacrificial flame, and double cornucopiae in left, with a star in either the right or left field
(see example above for star low in right field (BMCRE
Elagabalus 184 )
Here is my example with star in left field (BMCRE
Note the presence of what appears to be a plait of hair at the front of her hairstyle. I cannot tell if that is a braid of some kind or an ornament fitted on. I have another example which does not have this element. This variant is not mentioned in the references I use (BMCRE, RIC, RSC
(I have another example where the star is higher up in the left field, but it is in such atrocious condition I am reluctant to show it for what little it would add.)
The usual association for Concordia on the coins of the empresses referred to the harmony between the husband and wife. This is implied in the Reverse where Concordia calls for blessing on them with patera and altar, but even more directly in the type where the couple clasp hands. That is the imagery of her second Concordia reverse, seldom seen.
2. a rarely seen CONCORDIA type with the royal couple clasping right hands.
3. Very rare examples of a LAETITIA reverse holding a wreath in her r. hand and a rudder on globe in her left;
................(anyone care to pontificate on the significance of that imagery?)
4 and finally a VESTA type where she stands facing l. holding a branch and a scepter
................Not a surprising type for an empress who was a vestal virgin, as rare as that circumstance might be.