The right coin -
Caps of the Dioscuri Æ Cut As
Photo from Roma Numismatics Ltd.
Caps of the Dioscuri Æ As. Rome, 169-158 BC.
Obv - Laureate head of Janus; above l.
Rev - Prow right; above caps of the Dioscuri; before l; [ROMA] below.
The left coin above is shown below with the best example I could find on line.
Q. Caecilius Metellus Æ Semis
Photo from Roma Numismatics Ltd
Photo from ACR
Q. Caecilius Metellus Æ Semis. Rome, AD 130.
Obv - Laureate head of Saturn right; S behind
Rev - Prow of galley right; [Q•METE] above, S before, ROMA in exergue.
4.55 g, 2h. I measure 22.3 to 23.5 mm to outside edges.
I think the seller was conservative when they graded this coin gF. Most of the details that were on the coin when struck are still there. The flan was thin and low weight. I found 21 examples on line and in books and their average weight was 7.7 grams. There was not enough to fill some of the higher points of the die. It looks like a re-purposed coin that was hammered into a thinner round shape and then struck. Another possibility is the Semis was struck on Triens or Quadrans flan.
The following is information I normally store on a spreadsheet on some of my RR coins. It compares my coin to others.
Weight, grams 4.54
Weight - max 10.4
Weight - min 4.54, the next lightest coin was 6.1 gr
Weight - avg 7.7
Weight - st dev 1.3
Diameter - max 23.5
Diameter - min 22.3
Diameter - max 24.0
Diameter - min 19.0
Diameter - avg 21.9
Dia st dev 1.3
Cr 256 / 2a
BMCRR Rome 1056 - 1059
Bab Caecilia 22
NMWar 362 – 363
Grade, me VF, not much wear
Grade, seller gF, probably right, not much to look at
Centering Well centered
Strike good strike, but thin flan so high points missing
Flan flaws thin, low weight flan
Style average, meaning not too exciting
Damage none, but uneven tone giving less desirable eye appeal