黄金的單位 ?

//=== http://www.onlygold.com/tutorialpages/value_of_gold.asp
列了一堆 搞不清楚
1 oz == 1 英兩?
1 oz= 1 Troy Ounce
or
1 oz= 1 Avoirdupois Ounce

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Grain
Gram
Pennyweight
Tola
Avoirdupois Ounce
Troy Ounce
Tael
Troy Pound
Avoirdupois Pound
Kilogram
Ton
Metric tonne