What features of the rocks themselves would make them unsuitable to use as building stones? Name at least two rocks from different rock groups (igneous, metamorphic, sedimentary) and explain why they would not be good for building stones.

Features that make a rock not suitable for building structures are; 1. inability to withstand external forces like pressure, changes in temperature (heat and coldness), 2. instability. 3. Lack of strength ( weakness).

Explanation: Rocks used on building structures are strong, tough, durable and free of weathered soft particles and doesn't crack easily like granite, dolomite etc.

Example of Metamorphic rocks not suitable for construction are,

1. Schist: This is an example of foliated metamorphic rock which shows weakness trait.

2. Slate: This is unsuitable for construction because it breaks easily, it is not used because of its weakness.

Example of igneous rock not suitable are;

1.Pumice stone: this stone is unsuitable because of its light weight, and eroding character, it is so light that it could float in water, hence it lacks the characteristics to me used as construction stone..

2. Obsidian this is a volcanic glass, it is unsuitable because of its glassy appearance and known to be fragile.

Example of sedimentary rock

Conglomerate and Shale : These are unsuitable for construction because they can easily be eroded, and washed away by erosion, they are unsuitable because of their small grain size texture.