Section 3(1)(a) in The Black Money (Undisclosed Foreign Income and Assets) and Imposition of Tax Rules, 2015
(a)value of bullion, jewelery or precious stone shall be the higher of,-(I)its cost of acquisition; and(II)the price that the bullion, jewelery or precious stone shall ordinarily fetch if sold in the open market on the valuation date for which the assessee may obtain a report from a valuer recognized by the Government of a country or specified territory outside India or any of its agencies for the purpose of valuation of bullion, jewelery or precious stone under any regulation or law;