Chemical analysis of a rock can tell us what the rock is made of?

• A. its color only.
• B. its age.
• C. its magnetic properties.
• D. what the rock is made of.

Answer: (D)

The key idea is that chemical analysis directly reveals the elements and minerals present in a rock, showing what it is made of. By identifying the amounts of major elements (and often trace elements and oxides), you can determine which minerals are present and the overall composition of the rock. That composition is what defines the rock’s earthy make-up, its class, and how it formed.

Color isn’t a reliable indicator of composition on its own because colors can be affected by small amounts of impurities, weathering, or surface conditions. Age requires dating techniques that measure isotopes, not just what the rock is chemically composed of. Magnetic properties depend on specific minerals like magnetite and can vary widely even among rocks with similar overall chemistry, so they don’t fully specify composition.

So chemical analysis is the method that tells you what the rock is made of.