Final answer:
Sample 2's characteristics suggest it may be an igneous or non-highly metamorphosed metamorphic rock, with a coarse-grained texture, non-foliated structure, and containing some quartz. It lacks a greenish tint, banded texture, or schistosity, helping to narrow down its classification.
Step-by-step explanation:
When identifying and classifying a rock sample, it is crucial to assess its observable characteristics carefully. Using the criteria provided, one can determine the rock's type and potential origination. The fundamental characteristics provided suggest that Sample 2 could be an igneous or metamorphic rock, given its coarse-grained texture and lack of reaction to acid, which typically excludes the possibility of it being a limestone or marble. The presence of quartz, albeit not as a major component, and the absence of a greenish tint, banded texture, or schistosity, also guide the identification toward an igneous rock, specifically one that is not mafic due to the lack of green minerals like olivine or amphibole. Additionally, the provided characteristics imply that the rock is non-foliated, suggesting that it may not be highly metamorphosed, which could rule out certain forms of metamorphic rocks such as schist or gneiss. Comparison against a Rock and Mineral Guide would also include examining the rock's mineral content and texture to determine if it is felsic, intermediate, mafic, or ultramafic, and whether the texture indicates that it is intrusive (formed below the surface) or extrusive (formed at or above the surface).