Pattern Coins

The coin pictured below is a pattern piece. It represents a proposed design for a five cent coin. As patterns go, it's not particularly rare, listed as an R4 (76-200 known). Nor is it expensive, typically selling for around $1,200.00 today.  I owned one of these many decades ago - they were even less expensive then and I think I remember selling it for less than $700.00.

Image by Heritage Auctions, used by permission.

Patterns were sometimes issued to show members of Congress and other interested parties what new designs would look like. Patterns also include circulating designs struck on other metals and other oddities. 

However, from about 1858 to 1885, the U.S. Mint was producing patterns more as a business than for demonstration. Little to no records were kept, but often hundreds of specimens were made to be sold or traded. This secret manufacture is what makes it possible to own patterns today.

The practice of patterns for demonstration continues to this day, but patterns rarely leave the mint now and when they do, they may be subject to confiscation.

Martha Washington Patterns do come up for sale now and then. These were made in 1965 bearing a date of 1759. The Mint said all were destroyed, but apparently that wasn't quite true - probably because outside contractors produced some of them.

Resources:

What are Patterns - a pictorial essay

United States Pattern Coins (Official Red Books)

Martha Washington Patterns

Note:  All my coins are in a safe deposit box.  I keep nothing in my home. 

Contests and giveaways: http://coins.aplawrence.com/2014/05/contests-and-giveaways.html