CoinHELP!
1885 Trade Dollar (Proof Only) Value
FACTS:
The 1885 proof is the most rare Trade Dollar, and only exist as a proof, with only five minted and it's the most valuable in all grades. They don't come up for auction often and when they do they sell for well over a million dollars.

Here is a good article on Fake Trade Dollars: Fake Trade Dollars

Specifications:

Designer: William Barber

Diameter: 38.1 millimeters

Metal Content:
Silver - 90%
Copper - 10%

Weight: 27.2 grams

Edge: Reeded

Mint mark: None (for Philadelphia, Pennsylvania) above the D of DOLLAR on the reverse.

Mintage:  Proof:  5
Please Read Before Buying Trade Dollars! If a date is not listed here then it's fake or counterfeit. 
Fake Trade Dollar Guide


Have numismatic question click here
Date           Mintage    PR12      PR30    PR45     PR55      PR63     PR65

1885 Proof Only 5                                                      $1,565,000
CoinHELP! Coin Collector's Resource Web Site
1885 Trade Dollar Value
[Most Recent Charts from www.kitco.com]