Using Garnets in Sandpaper: A Colorful & Effective Choice
Why are garnets used in sandpaper?
a. Garnets have no other use.
b. Garnets have many crystal faces and therefore have sharp edges.
c. Garnets have a value of 8 or 9 on the Mohs Hardness Scale, making them very abrasive.
d. Garnets fracture easily and have abrasive edges.
e. The sandpaper takes on an appealing reddish color when the garnets are incorporated into it.
Final answer:
Answer:
Garnets are used in sandpaper due to their ability to fracture easily and form abrasive edges, combined with their suitable hardness on the Mohs Scale which makes them effective for smoothing materials. The correct option is D.
Explanation: Garnet is used in sandpaper primarily because of its physical properties that make it a very effective abrasive. The correct answer to why garnets are used in sandpaper is that garnets fracture easily and have abrasive edges (option d). Additionally, garnets are a good choice for sandpaper because they have a value of around 7 to 7.5 on the Mohs Hardness Scale, which makes them hard enough to smooth other materials, yet not too hard to be excessively costly.
While option e mentions an appealing reddish color, the color of garnet does not contribute to the functionality of the sandpaper, and other compounds such as kaolinite or talc can be white and still used as abrasives. Furthermore, while garnets do indeed have many crystal faces and sharp edges, option b is not the primary reason they're used in sandpaper; it's their fracture and abrasive properties that are key.
It is also important to note that using sandpaper to polish a mirror is not recommended. According to the law of reflection, a smooth surface produces a sharp image. Sandpaper's abrasive nature would create micro-scratches on the surface, making it unsuitable for applications requiring highly reflective and smooth surfaces like mirrors.