It is believed that there may have been a large number of black holes formed in the very early universe .
These would have quantised masses .
A charged “ elementary black hole ” ( with the minimum possible mass ) can capture electrons , protons and other charged particles to form a “ black hole atom ” .
We find the spectrum of such an object with a view to laboratory and astronomical observation of them , and estimate the lifetime of the bound states .
There is no limit to the charge of the black hole , which gives us the possibility of observing Z > 137 bound states and transitions at the lower continuum .
Negatively charged black holes can capture protons .
For Z > 1 , the orbiting protons will coalesce to form a nucleus ( after \beta -decay of some protons to neutrons ) , with a stability curve different to that of free nuclei .
In this system there is also the distinct possibility of single quark capture .
This leads to the formation of a coloured black hole that plays the role of an extremely heavy quark interacting strongly with the other two quarks .
Finally we consider atoms formed with much larger black holes .