"Pre-1933 gold coins" is a term used to describe a category of gold coins that were minted in the United States before 1933. These coins hold historical, numismatic, and investment value due to their gold content, rarity, and the fact that they were in circulation during a time when the U.S. was on the gold standard. 

Designs and Types:

1. Liberty Head Gold Coins: These coins feature the iconic image of Lady Liberty on the obverse (front) side. There were several denominations, including $1, $2.50, $5, $10, and $20. The most famous of these is the $20 Double Eagle coin.

2. Indian Head Gold Coins: The $2.50 and $5 coins in this series, also known as "Indian Head" coins, featured a Native American chief on the obverse and a bald eagle on the reverse.

3. Saint-Gaudens Double Eagle: Considered one of the most beautiful coins ever minted, the Saint-Gaudens Double Eagle ($20) features a stunning depiction of Lady Liberty holding a torch and an olive branch. The reverse side showcases a flying eagle.

Composition:

• Pre-1933 gold coins were typically made of 90% gold and 10% copper, resulting in a fineness of .900 or 21.6 karats. They contain the stated amount of gold in each coin, depending on the denomination.