Hi McMugle,According to Canada Customs & Revenue Agency (CCRA) you will be charged for a loose diamond from the US:10% excise tax on the price of the stone, translated into Canadian dollars;The excise tax then gets added to the base value of the stone for purposes of calculating GST = 7%;Plus Ontario PST = 8% :(1.07 + 1.0 x 1.10 x CAD $Priceor 1.265 x CAD $PriceYou should not pay US taxes though