Supergemming is a strategy in GemCraft for making more powerful gems without needing to increase the grade.
To create a Supergem, get a high-level gem and many lower level gems. Use combine to put the lower level gems into the high-level gem one by one. Every time you do this the damage and firing rate increases. Eventually you will get a high damage, high firerate gem.
Note that you should not combine gems that differ in grade by only one-by doing this, it is possible to lose significant amounts of damage.
In GemCraft Chapter Zero, the maximum possible firerate for towers is 279, or 640(?) in traps, before Yellow Gem's special is taken into account.
Differences Between Chapter 1 and Chapter 0 Edit
In GC1, the firerate is based on an integer value, and goes up a fixed amount depending on the gem added. It does not have a maximum.
In GC0, there is a cap on firerate (that varies depending on grade, but is never higher than 279), but while the firerate is increasing, it goes up exponentially rather than linearly.
Supergemming in GemCraft LabyrinthEdit
Since GCL, Red gems have the ability to increase their attack damage dramatically by killing enemies, due to their Bloodbound power. They are advised for supergemming.
How to do exactly:
First get a strong Bloodbound gem and place it in a tower. There should be no other things that can kill enemies but this one Red gem so it gets all the kills. This will lead to enormous damage values. Support the Red supergem with (up to 8) amplifiers that contain more Red gems to increase the impact of its ability. To anger the incoming waves is also important because it will cause more enemies what will lead to more kills for the gem to increase its damage value. The supergem can also be mixed with other colors if you want. The best combination is Red-Lime-Yellow because it hits multiple enemies with its huge damage value. The normal way of supergemming can still be used to increase the damage and speed further.