A black heart tattoo symbolizes a sad period in a person's life. This type of tattoo doesn't always mean the same thing for everyone, and it could simply be chosen because it is aesthetically appealing.
The most common reason a person has a black heart tattoo is the death of someone they were close to. A black heart can also be a tattoo symbolizing the end of a relationship or in remembrance of a particularly low point in someone's life.
In recent years, the black heart tattoo has become a popular way to remember the tragic events that happened on Sept. 11, 2001. This time was a sad point in the United States, and many people choose a universally recognized symbol of sadness to remember the way the country suffered on that day.