These cultivated rosettes are called “Black” not because of the dark tips, nor because as they grow they look like Echeveria “Black Prince”, but rather they were named after a fictional character named Doriet Black in a very popular Victorian novel from 1882.
In the novel, The Mystery of Doriet Black, Doriet Black was a fishmonger on the backstreets of Manchester, however he was also a secret agent married to a Prussian Princess. So you can see how the Victorian gentlemen of the time, amateur gardeners all, thought that might be an appropriate character to name a clever little sempervivum after. And they were right. We thank them for their resourcefulness.
However, things went bad in the sequel, The Deathly Hollow of Black, when Doriet Black turned out to be a triple agent in the service of an Italian Counterfeiter. Because of the uproar in 1886 over this 2nd novel, really more of a novella, the plant went out of style for over 100 years, returning to the succulent-growing public only in 1990.