How can two identical gems have different effects?

Question

I found two Blood Ember Speck gems both of same quality and level. However each have different effects.

So how can two otherwise identical gems have different effects, and can this happen with all gem types?

Screenshot of gems:

Answer 1

Gems in Torchlight II are split into two categories, there are normal gems (for example Venom Ember, Spark Ember, Ice Ember, etc) and rare gems (for example Blood Ember).

The difference is that normal gems always have the same attributes for each level of gem, while rare gems have randomly assigned attributes from a selection.

Here is a list of all gems in Torchlight II and their possible attributes, as you can see Blood Ember Speck is capable of having either of the following attributes:

Armor/Trinket: 7.2 Health Recovery per second
Weapon:        12 Health Stolen on Hit

-or-

Armor/Trinket: +48 Health
Weapon:        Conveys 35 Physical Damage over 5 seconds