Final answer:
The student's description aligns with the properties of quartzite, a metamorphic rock formed from quartz-rich sandstones. It is characterized by its hardness, conchoidal fracture, and resistance to acid.
Step-by-step explanation:
The student's question is describing characteristics associated with certain types of rocks and minerals. Specifically, the student seems to be referencing characteristics of quartzite, which is a common, crystalline-textured metamorphic rock that is hard, has a conchoidal fracture, and will not bubble in acid. Quartzite forms through the metamorphism of quartz-rich sandstones, where interlocking quartz crystals develop, and can be almost any color. These properties are consistent with the reference to hardness, conchoidal fracture, and a quartz composition described in the question.
Other descriptions provided pertain to rocks and minerals with different properties, such as those that fizz in HCl acid indicating the presence of calcite, or those that have a salty taste, indicating the presence of halite. Some descriptions allude to the texture and appearance, such as smooth, flat surfaces which could imply a slate or other fine-grained metamorphic rock, and various grain sizes from fine to course as well as their reaction to acid which add to identifying their mineralogical makeup.