I still can't get over all the generosity of the members on CT who have either sent me coins or are helping educate me. My continuing appreciation for your patience and generosity goes out to you. For instance, this is another coin @Victor_Clark sent to me. First of all, the coin is simply beautiful. It is so silver and sharp and pretty and the reverse is particularly meaningful to me. Victor, thank you soooo much! Here is my tentative attribution: Obv. IMP M IVL PHILIPPVS AVG, laureate, draped and cuirassed bust, bearded, right. Rev. AEQVITAS AVGG - Aequitas standing left, holding scales and cornucopia. 4.8 grams 22.22 mm. Questions: Am I incorrect to use the closest RIC (166) attribution I could find even though RIC 166 indicates the dimensions of that coin are 15,86 g and 28 mm? At 15.86 grams, it could not be my coin, right? Also, RIC 166 also has S - C in fields of the reverse and doesn't seem to be silver, or entirely silver as does the Philippvs coin Victor sent to me. RIC 166 is not the same coin. It is a sestertius whereas your coin is an AR Antoninianus. (Thanks to @Bing) Your coin is RIC IV Rome 27b - (Thanks to @Victor_Clark) I see, @Bing and @Victor_Clark. So the answer would be 'No. Do not use the closest attribution when there are glaring weight and size differences and differences on the reverse. Keep searching and don't get lazy." RIC IV Rome 27b 22mm 4.1gm IMP M IVL PHILIPPVS AVG; radiate, draped & cuirassed bust right. AEQVITAS AVGG; Aequitas standing left with cornucopia and scales.
What a fantastic gift! Great-looking coin I'd start with the emperor and denomination: clearly Philip I, as you identified, and your coin is a silver alloy with radiate bust, so it is an antoninianus. (I see that Victor chimed in with the answer as I was composing this post, but I will continue, focusing instead on how to arrive at that conclusion) Wildwinds (if that is the source you are using for attributions) does not have every possible coin of every emperor so there will be gaps in numbers. Different volumes of RIC also have different numbering schemes, so what you think might be a pattern for one era is not the same for another. Philip I's coins are in RIC volume 4c. I don't know if there is a free online version of that volume (probably not). If I had this coin and wanted to know its RIC number, I'd check Wildwinds, CNG's archives, and ACsearch. Checking Wildwinds (the page for Philip I, with thumbnail images), I used my browser's "find on page" to make it easier; search word "Aequitas", which narrowed the candidates from a gazillion to just eleven. Of those eleven, one was provincial, one was a sestertius, one was an as (the denomination is called an "as"), and one was an aureus so I didn't have to look carefully at those. Of the remaining seven candidates, one had a left-facing bust and so it didn't have to be carefully examined. The six remaining candidates which need a closer look (of the coins shown on Wildwinds' Philip I page, realizing it isn't complete) are RIC 27b 27 variant 57 82 variant 82 variant 82 variant Look closely at all six of those and you'll find the tiny differences which in this RIC volume led to assignment of a different number. If you are hunting for a coin's attribution and don't see it in Wildwinds, try CNG or ACsearch. I usually start with CNG's archives because it is easier to search, but I'm not usually searching for Roman Imperials which might be easier in Wildwinds. There's more than one way to find a coin's attribution/reference but this is generally how I go about it if I don't own an appropriate reference book.
@TIF - Thank you very much. I think I got lazy knowing I had to get to work this morning. I should have continued my search later when I had more time without feeling pressured. I'm sorry about that. I knew the weight was way off. It could not be the same attribution. I was on one website and I should have continued to a second (at least) for further comparison. Thanks for taking your time to write this out for me. I appreciate it.