Tiles from blackhole can be seen as a row or a column by blackhole is center, You can see number on it, When players make match, the number is be become lower each one every move. If the number remain to zero, the tiles will be destroyed and gems will be absorbed by the blackhole too as for special gems still have effect normally. Number on blackhole is be become lower each one every move same to former times before blackhole will create tiles again. Everything carry on as cycle until game is be ended.
Blackhole is main trouble to match for create special gems because gems-absorbed causes miss location of gems or no gems for match up. It obstruct to complete mission but special gems will be absorbed, they activate instantly what can destroy crystal or stone around blackhole or destroyed area of the gems.
Blackhole cannot be removed by any special effect and power-ups.