Gold and silver values then and now

Please send me the meaning and weight of one Mithqaal and one Dirham in the period of Rasool-Allah (Sallallahu Alaihi wa Sallam). Whether the cost of gold and silver were the same then or just like nowadays.

Praise be to Allah, the Lord of the Worlds; and may His blessings and peace be upon our Prophet Muhammad and upon all his Family and Companions. Actually, there was a considerable disagreement among jurists on the matter of deciding the weight of the Mithqal and the Dirham (units of weight) used during the era of the Prophet (peace be upon him). The difference emanates from the way followed by researchers while researching this issue. The best of such methods in this regard is the method of induction and follow up of these Mathaqeel (plural of Mithqal) [Dinars and Dirhams] that are preserved in the Arab and Western museums. This method was approved by Dr. Yousif al-Qaradhawi in his book, 'Az-Zakah/Obligatory Charity'. According to him, silver Dinar equals 2, 975 and golden Dinar equals 4, 25 grams. Based on that assumption, the rate of Zakah for silver is [2, 975 grams x 200 Dirham = 595 grams of silver]. The Zakah rate for gold is [4, 25 grams x 20 Dinars = 85 grams of gold]. It is well known that the difference in value between gold and silver is there since before the Prophet's time and until now. So it is a going on formula that the gold value is higher than that of silver, but with a rate varying from time to time.

Allah knows best.