Question

Which one of the following minerals does NOT show changes in optical properties upon exposure to UV light?

• A. Apatite
• B. Calcite
• C. Fluorite
• D. Scheelite

Hint:

Fluorite, calcite, and scheelite are classic fluorescent minerals, whereas apatite usually shows weak or no fluorescence.

Answer 1

The Correct Option is A

Step 1: Understanding UV light effect on minerals.
Some minerals exhibit fluorescence or phosphorescence when exposed to ultraviolet (UV) light, leading to changes in their optical properties such as color.

Step 2: Identifying fluorescence behavior.
Minerals that respond to UV light typically show visible light emission due to excitation of electrons, which is a key optical change.

Step 3: Analysis of Calcite.
Calcite commonly shows fluorescence under UV light, often emitting red, blue, or other colors depending on impurities present.

Step 4: Analysis of Fluorite.
Fluorite is well known for its strong fluorescence under UV light and is one of the classic fluorescent minerals.

Step 5: Analysis of Scheelite.
Scheelite also shows bright blue fluorescence under UV light, making it easily identifiable in mineral exploration.

Step 6: Analysis of Apatite.
Apatite generally does not show significant or consistent fluorescence under UV light compared to the others listed, so its optical properties remain largely unchanged.

Step 7: Final conclusion.
Thus, among the given options, apatite is the mineral that does not typically show changes in optical properties under UV light.
\[ \boxed{\text{Apatite}} \]