Final answer:
Long, fibrous inclusions in gemstones can create a visual effect called chatoyancy, akin to a 'cat's eye'. These inclusions reflect light uniquely due to their elongated crystal structure. Similarly, fibrous proteins play a key role in bone formation by providing a framework for bone minerals.
Step-by-step explanation:
Long, fibrous inclusions in gemstones may produce a visual effect known as chatoyancy, often referred to as a 'cat's eye' effect when it is present in cabochon-cut stones. The fibers, which are elongated crystal inclusions within the stone, act in a similar way to a silk strand, reflecting and scattering light to give this unique appearance. In gemstones like tiger's eye, these fibrous inclusions are integral to its aesthetic and structural properties. Similarly, in the context of bone formation, it is the fibrous proteins upon which bone minerals are deposited, giving strength and durability to the skeletal system. These fibrous proteins are typically strong, durable, and hydrophobic.