The cost of diamond varies directly as the square of its weight. Once, this diamond broke into four pieces with weights in the ratio $1 : 2 : 3 : 4.$ When the pieces were sold, the merchant got $\text{Rs. }70,000$ less. Find the original price of the diamond.
- $\text{Rs. }1.4 \text{ lakh}$
- $\text{Rs. }2\text{ lakh}$
- $\text{Rs. }1 \text{ lakh}$
- $\text{Rs. }2.1 \text{ lakh}$