If a sample of tourmaline is able to scratch a sample of kyanite, but kyanite cannot scratch tourmaline, then we can conclude that tourmaline is harder than kyanite. Hardness is a measure of a mineral's resistance to being scratched by another substance. The Mohs scale of mineral hardness is commonly used to compare the hardness of different minerals. On the Mohs scale, tourmaline typically has a hardness of around 7 to 7.5, while kyanite has a hardness of about 4.5 to 5.5.
Since tourmaline is capable of scratching kyanite, it means that tourmaline is harder than kyanite. However, kyanite cannot scratch tourmaline, indicating that tourmaline is also harder than kyanite. This comparison of hardness provides valuable information about the relative strength and durability of these minerals in terms of their resistance to scratching and abrasion.