Arrange the minerals based on the descending order of weatherability:

[A] Biotite > Augite > Garnet > Quartz

[B] Zircon > Tourmaline > Olivine > Muscovite

[C] Albite > Ilmenite > Hornblende > Olivin

[D] Anorthite > Spuite > Zircon > Titanite

Choose the correct answer from the options given below:

Correct option is A

✅ Correct option: (A) Biotite > Augite > Garnet > Quartz
Explanation (Why A is correct):
· Mineral weatherability broadly follows Goldich’s weathering series, which is the reverse of Bowen’s reaction series.
· Biotite
· Sheet silicate, rich in Fe and Mg
· Weak interlayer bonding → weathers rapidly
· Augite (Pyroxene)
· Chain silicate
· Moderate stability, weathers slower than biotite
· Garnet
· Framework structure but dense and resistant
· More stable than augite
· Quartz
· Strong Si–O bonds
· Most resistant mineral to chemical weathering
➡️ Thus, the descending order of weatherability is correctly represented in (A).
❌ Option (B): Zircon > Tourmaline > Olivine > Muscovite
· Zircon and tourmaline are among the most resistant minerals.
· Olivine weathers very rapidly and should appear near the beginning.
· Muscovite is more resistant than olivine.
· Hence, the order is incorrect.
❌ Option (C): Albite > Ilmenite > Hornblende > Olivine
· Olivine is the least stable mineral and should be first.
· Albite (Na-feldspar) is relatively stable compared to ferromagnesian minerals.
· The given sequence does not follow Goldich’s weathering series.
· Hence, incorrect.
❌ Option (D): Anorthite > Spuite > Zircon > Titanite
· Zircon and titanite are highly resistant minerals.
· Their placement suggests higher weatherability, which is wrong.
· Also, overall order is inconsistent with known mineral stability trends.
· Hence, incorrect.
�� Key Points to Remember
· Weatherability increases from felsic → mafic minerals.
· Quartz is the most resistant mineral.
· Olivine and biotite weather very quickly.