Neco 2024 Geography Question 6

A geologist collected a rock sample from a quarry in the Jos Plateau. The following observations were made: - The rock is coarse‑grained, pinkish, and feels gritty to the touch. - Under a hand lens, the mineral grains are identified as quartz, feldspar and mica in roughly equal proportions. - The rock contains visible interlocking crystals and no obvious layering. - A simple hardness test shows that the rock can scratch a glass plate (hardness >5.5). In addition, a laboratory analysis gave the following mass percentages for the minerals present in a powdered portion of the same rock: - Quartz: 33.2 % - Feldspar: 34.5 % - Mica: 32.3 % Answer the following: a) Identify the rock type based on the field and mineralogical description. b) Using the laboratory data, calculate the percentage composition of each mineral and comment on the agreement with the field observation. c) Explain the geological processes that could have led to the formation of this rock, referencing the rock cycle. d) Evaluate the suitability of this rock for use as a building material, considering its physical properties and mineral composition.