Question

Consider the following statements about Magnetism in minerals: Which of the statements is/are correct?

1. Quartz is a diamagnetic mineral that is weakly repelled.
2. Magnetite and Hematite are classified as ferromagnetic/ferrimagnetic.
3. Paramagnetic minerals like Garnet are strongly attracted and can retain magnetism.

• A. All
• B. i, iii
• C. ii only
• D. i, ii

Answer 1

Answer:

D. i, ii

Mineral Magnetism

• Minerals exhibit different types of magnetic behavior based on how their electrons respond to an external magnetic field.

• Diamagnetism: This is a weak form of magnetism where minerals are weakly repelled by a magnetic field. The effect arises from the orbital motion of electrons. All minerals are diamagnetic, but this effect is often masked by stronger forms of magnetism.

• Paramagnetism: In paramagnetic minerals, there are unpaired electrons that align with an external magnetic field, causing a weak attraction. This attraction is generally stronger than diamagnetism. Paramagnetic minerals do not typically retain magnetism once the external field is removed. Garnet is an example of a paramagnetic mineral.

• Ferromagnetism and Ferrimagnetism: These are the strongest forms of magnetism, characterized by a strong attraction to magnetic fields. In ferromagnetic materials, the magnetic moments of atoms align parallel to each other, creating a strong internal magnetic field. Ferrimagnetic materials are similar but have opposing magnetic moments, resulting in a net magnetic moment. These minerals can retain their magnetism even after the external field is removed, a property known as hysteresis.

Specific Mineral Examples:

• Quartz (SiO₂): Quartz is primarily diamagnetic. Its electron structure causes it to be weakly repelled by a magnetic field.

• Magnetite (Fe₃O₄): Magnetite is a classic example of a ferrimagnetic mineral. It is strongly magnetic and is often used in experiments demonstrating magnetism.

• Hematite (Fe₂O₃): Hematite exhibits ferrimagnetism, although it is generally less magnetic than magnetite. It is a common iron ore.

• Garnet: While some garnets can show slight paramagnetic behavior due to the presence of certain ions, they are not strongly attracted and do not typically retain magnetism like ferromagnetic materials. The statement that paramagnetic minerals like Garnet are strongly attracted and can retain magnetism is incorrect.