Under these conditions, you can probably expect your car battery life to be about  six years. On average, a car battery lasts between two and five years. If you live in the northern United States, your car battery lifespan will be longer, because youâre in a cold climate. Warm climates tend to increase damage due to sulfation and water loss.
Granite being a natural stone is composed of many different minerals, and iron may be one of them. Untreated (non-resin sealed) granite is more likely to exhibit rust staining than resin-sealed granite. However, even resin-sealed slabs and tiles can rust if not properly protected using a quality stone impregnator.
There are lots of different metals and lots of different stones. Aluminium, for example is less dense (lighter) than granite Iron is more dense than pumice (a volcanic rock that actually floats on water). Even rocks such as granite vary in density. To answer your specific example, as granite contains heavy metals it would normally be denser than iron. Obsidian is likely to be less dense than iron as it contains lighter elements. Generally the metals are heavier than stones.But not in all cases.