Gorgeous coins Steve!! Ok, who's the obol and litra expert...to answer Pishpash---not me unfortunately...I would have to research it as usual. I knew this new fangled gizmo called a computer would come in handy LOL
http://www.forumancientcoins.com/numiswiki/view.asp?key=Denomination scroll-down to the bottom of that link to find a great table (I've printed-out that baby and pinned it to the wall) ... it's money!! => the weight of an obol dances around a bit (depending upon the region ... please refer to the sweet link) ... the weight of a litra seems to be "approximately" 0.86 grams according to the Sicilian scale (man, I love Sicilian coins!!)
=> 100% => Doug usually loves flyin' in right about now to give an explanation of why these weights "ain't cast in stone!!" ... I merely use that table as an approximate-guide (one data-point) => earn your Masters degree and figure it out for us!!
Amen to that Brother Pishpash...I guess that's way they say.."It's all Greek to me.." when something seems incomprehensible...
nice lookin' scallop pish. i was surprised by the size, my first intuition was that is was much larger...like twice as big. yeah, i've kind of given up on exact greek coin units. pick one that's close and i don't think anyone will argue with you much.
The camera is on charge, I will take a photo for JA tomorrow "on the finger" it is a tiny little thing. I will print out the table, different websites give varying weights, and I think you are right Chrsmat, closest will do.
Searching acsearch.info, I found 4 fractional Tarentums of your type: two "obols" (0.74 and 0.84 g) and two "hemiobols" (0.19, 0.28). Granted that the weights of these fractions vary widely, the weight of your coin seems to fall at about the midpoint of the average weights of these two denominations. So, perhaps it is a tritartemorion. What I found interesting is that on all four of these coins the dolphin is facing right, whereas on your coin it appears to face left!
Given its place of origin, I'd call it a litra or hemilitra. Better yet, just say AR 9mm For what it's worth, I have a similar coin and NGC called it a litra. Also according to NGC, my coin weighs 0.56 gm. I don't trust the accuracy of my digital scale at the low end and have not reweighed it. CALABRIA, Tarentum 325-280 BCE AR litra, 11 mm, 0.56 gm Obv: cockle shell Rev: dolphin right, trident* below (I think it might be a bunch of grapes) Ref: Vlasto 1530 (if grapes rather than trident, Vlasto 1527) from Heritage Auctions 13 Nov. 2014 Formerly slabbed, NGC Choice VF 5/5-3/5; cert# 3601372-003 *The auction description said "trident below" but I think it is grapes and therefore Vlasto 1527. It will remain a guess though because of condition. I did an acsearch of "Calabria, litra" and found many more, including left-facing dolphins. The designation of litra vs. hemilitra within that general weight range was inconsistent but most were labeled "litra".