Is there Zakah due on diamond?

Q 1: I have a diamond set that I have displayed for sale for four months. Is Zakah (obligatory charity) due on it? A: If a year has passed and this diamond set is still on display for sale and has not been sold, Zakah is due on it, because it is considered a commercial commodity. Thus, it should be evaluated after the passing of a full Hawl (one lunar year calculated from the time a property reaches the minimum amount upon which Zakah is due). If the value equals the Nisab or more at the time of evaluation, then 2.5% should be paid of its estimated current value. Similarly, if another Hawl passes while it is displayed for sale, it should be evaluated upon the completion of the Hawl and 2.5% of its estimated current value should be paid as the due Zakah. (Part No. 8; Page No. 113

A: If a year has passed and this diamond set is still on display for sale and has not been sold, Zakah is due on it, because it is considered a commercial commodity. Thus, it should be evaluated after the passing of a full Hawl (one lunar year calculated from the time a property reaches the minimum amount upon which Zakah is due). If the value equals the Nisab or more at the time of evaluation, then 2.5% should be paid of its estimated current value. Similarly, if another Hawl passes while it is displayed for sale, it should be evaluated upon the completion of the Hawl and 2.5% of its estimated current value should be paid as the due Zakah. (Part No. 8; Page No. 113)