Two elements determine the ancient Half Shekel weight (or Machtzis haShekel - Mahassit HaSheqel) and hence price
a. Barley grains count: The number of barley grains with the weight equivalent to a "Half of a Shekel" - The 'Shekel' originally was a weight unit.
1. Ashkenaz: 160 grains of barley - in accordance with the Mishna and Rambam, (Shekalim 1/5)
2. Sefarad: 183 grains of barley, which are "3 drachmas".
b. Barley grain weight: What should be considered as the weight of barley grains has been determined about 1000 years ago by the Geonim, the Jewish Babylonian religious leadership, and again recently after WWII by rabbi Chaim Naeh, this time in (a rare) agreement with the Chazon Ish.
1. Geonim and Rishonim: 0.044 grams per grain
2. Rabbi Chaim Naeh, and the Chazon Ish: 0.050 grams per grain.
Price calculation
Price calculation is as follows:
hw : the weight of half-shekel in grams
sw : the weight of an ounce of silver in grams
gc : the count of grains in a half shekel (ashk:160, or sfrd: 183)
gw: the weight of a grain in grams (geon:0.044 or naeh:0.050)
p : price | sr : silver rate (in dollars) | dr : dollar to shekel rate (leave 1 for USD)
hw = gc x gw // halfshekelWeight = grainCount * grainWeight
p = (hw / sw) x sr x dr // price = (halfshekelWeight / silverOunceWeight) * silverRate
// and for shekels: * dollarRate
The 1/2 Shekel price calculation explained
For performing the calculation please go back to the home page
50 years ago a stash of silver coins, coined in the city of Tyre on the Lebanese coast, along with a smaller sack with copper coins, were found in the Druze town of Osfiyya on the Carmel mountains near Haifa, during house construction.
Osfiyya is the location of the ancient Jewish town of Huseifa. The coins are from three years before the Jewish Temple destruction, a time when the Romans headed by Aspasyanos were not allowing passage through the Galilee to Jerusalem. It has been determined that these were actual half Shekalim, from the time of the temple that did not reach it. (Originally printed in YBZ Kadmoniot magazine, reprinted in the Bar Ilan University Shabbat weekly leaflet. See the presentation for the same)
It is not clear why there is no deeper interest in checking the weight and silver content of these coins ?!!