Union Bullion is a separate scheme or program offered by Union Bank of India for the import and sale of gold. The bank, which is one of the nominated agencies for (Gold) import, operates a Bullion (Designated) branch that facilitates the import of gold on a consignment basis or back-to-back basis. 

Here are some key points regarding the import and sale of gold under the Union Bullion scheme:

• Consignment Basis : The bank imports gold on a consignment basis from the approved suppliers through its Treasury Branch. The ownership of the imported gold remains with the overseas supplier until the final sale is made to the customer and the price is fixed. Customers specify the quantity they desire to purchase, and the bank contacts the supplier to fix the price. The gold is delivered to the customer upon payment in Indian Rupees at the ongoing or agreed rate.
• Back-to-Back Basis : Customers can place an order with the bank specifying the quantity and desired price range. The bank then places an order with an approved supplier. Once the terms, including price and delivery date, are agreed upon, the customer is informed, and the gold is delivered upon full payment in Indian Rupees.
• Sale of Gold : The bank can sell gold from its consignment stocks to customers at unfixed prices, provided the price is fixed within 11 calendar days from the date of delivery. The bank may also sell gold on a fixed price basis, where customers specify the desired quantity, and the bank fixes the price before delivery.
• Margin Requirements : As per RBI guidelines, the bank is required to collect a 100% margin in cash for the provisional value of gold and an additional margin (typically 10-15%) to account for price fluctuations.

It's important to note that the information provided is based on the details you shared, and specific details of the Union Bullion scheme may vary depending on the bank and its policies.