What would you observe when crystals of iron (II) sulphate are heated in a test-tube strongly?

Explanation

We observe the following when crystals of iron (II) sulphate are heated in a test-tube strongly:
Initially, drops of water are condensed at the mouth of the test tube (cooler part). An anhydrous residue is seen which is non-crystalline (powdery) in nature.
The crystals lose its green colouration on further heating.
On further heating strongly, the residue changes to brown residue of ferric oxide with the evolution of mixture of sulphur dioxide and sulphur trioxide gases.