Diamagnetic materials have following properties:

• In a diamagnetic material, the magnetic lines of forces due to an applied field are repelled.

• when suspended in a uniform magnetic field, diamagnetic materials set their longest axis at right angles to the direction of the field and the shortest axis is along the direction of the field.
• when placed in a non-uniform magnetic field, the diamagnetic materials move from stronger parts of the field to the weaker parts.
• relative magnetic permeability of diamagnetic materials is always less than unity that is

μ_r < 1

Reason is given in another article

• Magnetic susceptibility if diamagnetic materials is always negative.

Reason is given in another article

• Magnetic susceptibility of diamagnetic materials does not change with temperature, that is they do not obey Curie law

Reference: This article is referred from my book “electrical engineering materials” having ISBN 978-81-272-5069-0. In case of any doubt, you can put your question in the comment section.