Many things can cause a coin to discolor. Some of the most common are exposure to heat or chemicals; nickels are also a favorite coin for middle- and high-school electroplating experiments.
The coin is called an Indian Head nickel or a buffalo nickel, not "buffalo head" - after all, it shows the entire buffalo! Please see the Related Question for more details.
The Romance of Copper Gulch - 1914 was released on: USA: May 1914
That sounds like a U.S. Liberty nickel, except none were minted in 1914. They were produced from 1883 through 1912, and are made of 75% copper with 25% nickel, which is the same blend still used today.
The Indian Wars - 1914 was released on: USA: August 1914
An Indian Eclipse - 1914 was released on: USA: 29 July 1914
The Indian Suffragettes - 1914 was released on: USA: 6 November 1914
An Indian's Honor - 1914 was released on: USA: 21 February 1914
Indian Fate - 1914 was released on: USA: 11 February 1914
Lo The Poor Indian - 1914 was released on: USA: 15 April 1914
Please take another look at your coin and post a new question with some more details that could help to ID it.First, Liberty Head nickels (note the spelling!) were discontinued in 1912. All nickels made in 1914 carry the famous Indian head design.Second, the US never issued a gold nickel because it would be worth at least a hundred times as much as 5 cents even back then, and thousands of times more today.There were 5 DOLLAR coins struck in 1914 that were about the size of a nickel but they also have an Indian head design.
The cast of The Romance of Copper Gulch - 1914 includes: Joe Ryan Josephine West
A 1914 penny with no mint mark is worth about $1.50.