From the CoinWeek IQ Encyclopedia:
20 Euro Cent (2002-Present)
The 20 euro cent coin is the second of three “nordic gold” coins in the euro series (“nordic gold” is an alloy of 89% copper, 5% aluminum, 5% zinc and 1% tin, originally developed by the Swedish Mint for its 1991 10-kronor piece). The coin has an attractive crimped rim that makes it easily distinguishable from the other minor euro coins. It’s made of brass and tends to hold its brilliance a tad longer than the copper-plated steel 1, 2, and 5 euro cents once put into circulation. The 20 euro cent is valued at 2/10th of a euro and is roughly the equivalent of the U.S. quarter dollar in terms of its spending power.
Composition: brass | Weight: 5.74 grams | Size: 22.25 mm
National Side (Side Unique to the Issuing Country)
Designer: Josef Kaiser
Head-on view of the front gate of Belvedere Palace. The inscription EURO CENT wraps around the inner circle. The numeral “20” is centered left to right near the middle of the field. Beneath it is the Austrian flag and the year.
Central devices and inscription encircled by an inner border. Stars representing each of the original 12 member states of the Eurozone circle the perimeter of the coin and are bordered by a raised and crimped outer rim.
Designer: Luc Luycx
Type 1: Six horizontal line segments containing stars at each end. Individualized representations of the 12 original Eurozone states are in the center and divide the stripes. A large numeral “20” and the inscription EURO CENT, all italicized, are to the right. The designer’s initials “LL” appear to the right of the Earth. Design encircled by a raised rim.
Type 2: Same as Type 1, except a full representation of Western Europe replaces the representations of the 12 original Eurozone states. Crimped Rim.
The Austrian Mint strikes the 20 euro cent in three unique finishes: a business strike intended for general circulation; a satin finish specimen strike produced for collector sets; and proofs, which are sold in annual proof sets.
CoinWeek Austria 20 Euro Cent Business Strike Price Guide
CoinWeek Austria 20 Euro Cent Satin Finish (Mint Set) Price Guide
CoinWeek Austria 20 Euro Cent Proof Coinage Price Guide