Zecca di Roma, denario ¹, 225 d.C², RIC IV/II 182c, BMC VI 279/280, C/IV 576, indice di rarità "C".

D. IMP C M AVR SEV ALEXAND AVG³. Alessandro Severo busto laureato e drappeggiato a destra. 
R. VIRT - VS AVG⁴. La Virtus di Augusto in piedi a destra, sorregge una lancia con la punta in basso e poggia la mano sinistra su uno scudo.
 

La ricerca nel web ha prodotto i seguenti risultati:

1. http://www.wildwinds.com/coins/sear5/s7934.html Severus Alexander Den "Virtus" Severus Alexander AD 222-235 Silver Denarius "Alexander is a strong and brave leader." Obv: IMP C M AVR SEV ALEXAND AVG - Laureate bust right, draped. Rev: VIR-T-VS AVG - Virtus standing right, holding reversed spear and leaning on shield with left hand. Rome mint: AD 225 = RIC IVii, 182c, page 84 - Cohen 576 - SEAR RCV II (2002), #7934, page 650 (VF $25 - XF $75) / 2.81 g. Coin sold at 20/10/2004 (dd/mm/yyyy) Final sale value in local currencies GBP 8.60 USD 15.51 JPY 1682.37AUD 21.31 RUB 451.65 CAD 19.50 EUR 12.39
2. http://www.wildwinds.com/coins/ric/severus_alexander/RIC_0182.1.jpg Severus Alexander Den "Virtus" SUPERB+ Severus Alexander AD 222-235 Silver Denarius "Alexander is a strong and brave leader" Obv: IMP C M AVR SEV ALEXAND AVG - Laureate bust right, draped Rev: VIRTVS AVG - Virtus standing right, holding reversed spear and leaning on shield with left hand Rome mint: AD 222-228 = RIC IVii, 182c, page 84 - Cohen 576, 3.24 g. US $43.00 Ended: Jul-08-03
3. http://www.wildwinds.com/coins/ric/severus_alexander/RIC_0182.2.jpg Severus Alexander Den "Virtus" Severus Alexander AD 222-235 Silver Denarius "Alexander is a strong and brave leader." Obv: IMP C M AVR SEV ALEXAND AVG - Laureate bust right, draped. Rev: VIRTVS AVG - Virtus standing right, holding reversed spear and leaning on shield with left hand. Rome mint: AD 225 = RIC IVii, 182c, page 84 - Cohen 576 - SEAR RCV II (2002), #7934, page 650 (VF $25 - XF $75)3.52g. bid: US $14.51 Ended: Jun-02-04
4. http://www.wildwinds.com/coins/ric/severus_alexander/RIC_0182.3.jpg Metal: Silver Obverse Condition: Very Fine (VF) Reverse Condition: Fine (F) Severus Alexander A.D.222-235 AR Silver Denarius, Sear 2238. MARCVS IVLIVS GESSIVS ALEXIANVS BASSIANVS was born in Phoenicia in 208 to Gessius Marcianus and Julia Mamaea. Mamaea's aunt was Julia Domna, Septimius Severus' wife. When Macrinus was murdered in 218, Alexianus' cousin Elagabalus became Emperor. Alexianus was named Caesar in 221, and when Elagabalus was murdered on March 6, 222, he became Emperor as Marcus Aurelius Severus Alexander. He ruled extremely well, always under his mother's influence. However, loved by the people but loathed by the legions, Maximinus' soldiers murdered them both near Mainz on March 22, 235. Obv: IMP.C.M.AVR.SEV.ALEXAND.AVG. Laur. bust right. Rev: VIRTVS AVG. Virtus standing holding spear and leaning on shield. Current Bid: $15.00
5. http://www.wildwinds.com/coins/ric/severus_alexander/RIC_0182.4-o.jpg 

http://www.wildwinds.com/coins/ric/severus_alexander/RIC_0182.4-r.jpg ORC48 - SEVERUS ALEXANDER Denarius Virtus, EF Severus Alexander, AR denarius, IMP C M AVR SEV ALEXAND AVG, laureate and draped bust right. / VIRTVS AVG, Virtus, personifying bravery and courage, stands resting his hand on a shield, and holding a reversed spear. RSC576; RIC 182; BMC 278-82, (2.8 gm.), EF, rev. weak strike. Marcus Julius Gessius Alexianus was adopted at the age of 13 by his cousin the Emperor, Elagabalus, at the insistence of the family matriarch, Julia Maesa. This set-up enabled Maesa to have the despised Elagabalus killed the following year, with Alexander being hailed by the troops as Emperor. Because of his youth, his grandmother exercised control behind the scenes, but neither one was popular with the army. This proved fatal to them in 235, during a war with the Germans, when their own troops executed them. Currently $32.50 Dec-19-00
6. http://www.wildwinds.com/coins/ric/severus_alexander/RIC_0182.5.jpg Severus Alexander Den "Virtus" Severus Alexander AD 222-235 Silver Denarius "Alexander is a strong and brave leader." Obv: IMP C M AVR SEV ALEXAND AVG - Laureate bust right, draped. Rev: VIRTVS AVG - Virtus standing right, holding reversed spear and leaning on shield with left hand. Rome mint: AD 225 = RIC IVii, 182c, page 84 - Cohen 576 - SEAR RCV II (2002), #7934, page 650 (VF $25 - XF $75)2.22g Coin sold at 06/10/2004 (dd/mm/yyyy) Final sale value in local currencies GBP 9.98 USD 17.80 JPY 1977.96 AUD 24.58 RUB 520.22 CAD 22.46 EUR 14.45

Concludo osservando che le caratteristiche fisiche e di stile della moneta in esame  appaiono compatibili con i conî d'epoca.

Un saluto cordiale.
Giulio De Florio
www.monetaromana.it
 

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Note:
(1) Il denario di Severo Alessandro pesava in media attorno ai 2,9 g ma con una larga dispersione dei valori attorno a questa media, la maggiore concentrazione di peso era nella fascia compresa tra 2,22 e 3,65g. Su 335 denari presi in considerazione da BMC, solo 1 pesava meno di 2,05g e 8 meno di 2,21. Il diametro si aggirava tra i 19 e i 21 mm. L'asse di conio, per i denari di A. S. catalogati come BMC VI 278 .. 282 è ad ore 6.
(2) Il sito francese, http://www.i-numis.com/rome/articles/alexandre/alexandre.html sostiene che la moneta appartenga alla quinta emissione della zecca con la seguente datazione: 225 d.C.
(3) IMPerator Caesar Marcus AVRelius SEVeverus ALEXANDer AVGustus. Per la sintesi storica su Alessandro Severo si rimanda ad altra pagina di questo sito (cliccare qui) oppure al riassunto cronologico all'interno del sito francese sopra menzionato.
(4) La tipologia dei rovesci di questo sovrano è piuttosto convenzionale; deità e personificazioni, come Giove, Marte, il Sole, Romolo, l'Aequitas, Annona, Felicitas, Fortuna, Liberalitas, Libertas, Pax, Providentia, Salus e Virtus si ritrovano regolarmente. Fanno eccezione alcuni tipi architetturali, come il Colosseo, il tempio di Giove Ultore, le Terme di Alessandro.