Which of the following mineral properties includes the descriptions conchoidal, splintery, irregular? \( \begin{array}{lllll}\text { A. cleavage } & \text { B. streak } & \text { C. fracture } & \text { D. luster } \\ \text { Silicates always contain } & \text { A. aluminum } & \text { B. oxygen } & \text { C. quartz } & \text { D. iron }\end{array} \)

The property you're looking for is "fracture." When a mineral breaks without a smooth surface, it can showcase various patterns such as conchoidal (curved shells), splintery (sharp edges), or irregular (random fractures). This property describes how the mineral's structure breaks apart, which can tell you a lot about its composition and durability! As for silicates, they are characterized by their silicon-oxygen tetrahedron structure. So, the correct answer here is "B. oxygen." Silicates are the most abundant group of minerals in the Earth's crust and play crucial roles in geology and materials science. Understanding their composition helps in everything from construction to electronics!