A tradeable commodity or instrument, a trading system for a plurality of such commodities, a method of trading using such a system and security systems related thereto. The tradeable instrument comprises a secure container constituted by a transparent cover (12), a stone holder pad (14), a set of diamonds (15), a diamond or stone holder (16), a data card (18), a bottom cover (20) and a tamper evident band (22) interconnected into a secure, tamper-evident envelope. The data card (18) incorporates physical and digital security features. In addition, at least one externally readable programmable logic device is incorporated in the tradeable instrument card. The tamper evident band (22) is shrunk onto the tradeable instrument card and includes physical security features in the form of holographic foils incorporated in the band.