Simply from the name of the precious stone (which ultimately derives from Latin ruber "red"), which is the birthstone of July. It came into use as a given name in the 16th century [1].
We use a combination of data from the internet, and our own Machine Learning models to make these predictions.
In a gist, we use a Machine Learning model trained on a diverse global dataset of 100m+ names, and use it to predict different traits for a person based on first name!
NameGuessr guesses a person's nationality, age, and gender based on their name. We also try to give insightful info around the name's origin, name meaning, and name pronounciation.