Black habanero is an alternative name often used to describe the dark brown variety of habanero chilis (although they are slightly different, being slightly smaller and slightly more sphere-shaped). Some seeds have been found which are thought to be over 7,000 years old. The black habanero has an exotic and unusual taste, and is hotter than a regular habanero with a rating between 400,000 and 450,000 Scoville units. Small slivers used in cooking can have a dramatic effect on the overall dish. Black habaneros take considerably longer to grow than other habanero chili varieties. In a dried form, they can be preserved for long periods of time, and can be reconstituted in water then added to sauce mixes. Previously known as habanero negro, or by their Nahuatl name, their name was translated into English by spice traders in the 19th century as "black habanero". The word "chocolate" was derived from the Nahuatl word, xocolātl [ʃoˈkolaːt͡ɬ], and was used in the description, as well (as "chocolate habanero"), but it proved to be unpronounceable to the British traders, so it was simply named "black habanero".