Pick up the correct statement from the following:
🪨 Understanding the "Natural Bed" of a Stone
This question tests the definition and characteristics of a stone's "natural bed," which is a crucial concept for durable stone masonry.
🔬 Detailed Analysis of the Statements
A. The distinct plane of division along which a stone can easily be split, is called natural bed of stone
This statement is correct. It provides the fundamental definition of a natural bed. It is the original plane on which the rock material was deposited, creating a natural weakness or grain. A skilled mason can identify this plane and use it to easily split the stone.
B. The natural bed of sedimentary rocks is along the planes of stratification
This statement is correct. Sedimentary rocks are formed in layers (strata). These layers are the visible representation of the natural bed. Therefore, the planes of stratification are the natural beds of sedimentary rocks.
C. The natural bed of igneous rocks is not defined
This statement is correct. Igneous rocks are formed from the cooling of molten magma. They have a crystalline, granular structure where the minerals are randomly oriented. They do not form in layers and therefore have no distinct planes of weakness. They are equally strong in all directions and do not have a defined natural bed.
D. All the above
This is the best answer. Since statements A, B, and C are all individually correct and factual statements about the natural bed of stones, the most comprehensive answer is "All the above".
📊 Summary of Natural Bed in Different Rock Types
| Rock Type | Has a Natural Bed? | Description |
|---|---|---|
| Sedimentary | Yes | The natural bed corresponds to the planes of stratification (layers). |
| Igneous | No | Crystalline structure with no layers; strength is uniform in all directions. |
| Metamorphic | Yes (Foliation) | The natural bed corresponds to the planes of foliation (mineral alignment). |
💡 Study Tips
- Natural Bed = Natural Weakness: Think of the natural bed as the "grain" of the stone, similar to the grain in wood. It's the easiest direction to split it.
- Sedimentary = Layers: Sedimentary rocks are defined by their layers (stratification), so their natural bed is always along these layers.
- Igneous = Interlocked Crystals: Igneous rocks are a solid mass of interlocked crystals with no inherent layers, so they have no natural bed.
- Rule for "All of the above": When each statement is a correct, factual definition or description, "All of the above" is a very strong possibility.