The phrase “diamond in the rough” pertains to a person or an item that has potential that, to the untrained eye, is overlooked or missed completely. The Japanese have a saying that’s not dissimilar to the phrase “diamond in the rough” — a jewel, unless polished, will not sparkle (tama migakasareba hikari nashi).
Mary McLeod Bethune (1875 – 1955) was responsible for establishing the Bethune Nursery School — the first child care centre in Lynchburg (Virginia) — in February 1936. She gave the school its motto: “Invest in the human soul. Who knows, it might be a diamond in the rough.” Almost a century later, Mary Bethune Academy as it’s now known, believes this as much now as when the Nursery School first threw open its doors.
On February 3, 1877, the Quebec Saturday Budget newspaper ran an article about the annual anniversary meeting of the Young Men’s Christian Association held the previous Thursday in the Music Hall. The audience was said to be very large, select and appreciative and the Hall was said to be well heated. In the report, readers found the following:
There he was taken hold of by good John Currie, himself a brand snatched from the burning, a diamond in the rough — a good, honest, faithful, trusting Christian, who received just such men into his house, although he scarcely ever knew where he was going to get his next meal, and prayed over them until they were brought to God. This young engineer was now leading a sober life, — a gem of Christian piety and Godly service.
The phrase is a figurative interpretation of the literal meaning as it pertains to unpolished state of diamonds, especially those that have the potential to demand the highest prices once polished. The first recorded implied use of the phrase “diamond in the rough” can be found in John Fletcher’s A Wife For A Month written in 1624, where the author writes:
She is very honest, and will be as hard to cut as a rough diamond.
Diamond is from the early 14th century from the Old French word diamant, which is from the Middle Latin word, diamantem. This Latin word is from an even older Latin word, adamantem which means “the hardest metal.” As a side note, the word “adamant” is from this same Latin word.
Rough is from the Old English word ruh which means “rough, untrimmed, uncultivated.” This hails from the Germanic word rukhwaz which means rough. As a side note, use of the word rough to mean “approximate” is first recorded in 1600.
Based on the etymology of the words “diamond” and “rough” it is reasonable to assume that it is highly unlikely any author before John Fletcher made use of the phrase prior to the publication of his book.
Historically Speaking 