It becomes a non-crystalline, powdery anhydrous salt.

The hydrated (pentahydrate) form is chalcanthite, a bright blue crystal. The rare anhydrous ore form is called chalcocyanite, a gray or pale-green powdery rock.

(If heated to 650 °C, copper sulfate becomes copper oxide and sulfur trioxide.)

It becomes a non-crystalline, powdery anhydrous salt.

The hydrated (pentahydrate) form is chalcanthite, a bright blue crystal. The rare anhydrous ore form is called chalcocyanite, a gray or pale-green powdery rock.

(If heated to 650 °C, copper sulfate becomes copper oxide and sulfur trioxide.)

From Wikipedia:

Copper(II) sulfate is the chemical compound with the formula CuSO4. This salt exists as a series of compounds that differ in their degree of hydration. The anhydrous form is a pale green or gray-white powder, whereas the pentahydrate, the most commonly encountered salt, is bright blue. The anhydrous form occurs as a rare mineral known as chalcocyanite. The hydrated copper sulfate occurs in nature as chalcanthite (pentahydrate), and two more rare ones: bonattite (trihydrate) and boothite (heptahydrate). Archaic names for copper(II) sulfate are "blue vitriol" and "bluestone".[1]