Building Stones MCQ with answer and solution

Concept

Properties of Building Stones

Formula

N/A

Step-by-step solution

1. Evaluate Statement 1: Granite is hard and difficult to dress, making Statement 1 incorrect. 2. Evaluate Statement 2: Slate has excellent cleavage suitable for roofing, making Statement 2 correct. 3. Evaluate Statement 3: Good building stone must have a specific gravity greater than 2.7, making Statement 3 correct. 4. Select Option (b) as Statements 2 and 3 are correct.

Explanation

Option B (2 and 3 only) is correct because slate easily splits into thin, flat sheets due to its cleavage, making it ideal for roofing, and a good building stone should generally have a specific gravity greater than 2.7. Statement 1 is incorrect because granite is an extremely hard rock that is difficult to dress, not soft.

Shortcut

To remember key properties of building stones, use the quick guide "HARD Slate 2.7": - Granite is HARD: Extremely hard igneous rock, difficult to dress and not soft. - Slate splits into Sheets: Excellent cleavage makes it perfect for thin roofing tiles. - Specific Gravity > 2.7: Good quality building stone requires high density with SG greater than 2.7.

Common mistake

A common mistake is selecting option D by incorrectly assuming that granite is a soft, easily carved stone suitable for delicate ornamental work, whereas granite is actually an unyielding, hard igneous rock that is very difficult to dress. Another frequent mistake is selecting option A by forgetting that a good quality building stone must have a high specific gravity, typically greater than 2.7.