Assuming a furnace with a 78 percent efficiency, consumers should expect to pay roughly $12.96 per million BTUs of heat. While prices for gas and electricity vary over time and by region, gas furnaces typically cost much less to operate than electric furnaces or heaters.lectric space heaters all have AFUE ratings of 100 percent. Assuming an electric heater with 100 percent efficiency, homeowners should expect to pay roughly $34.32 per million BTUs of heat. Natural gas is generally sold in therms, where one therm is equal to 100,000 BTUs.
Rocks- A rock is made up of 2 or more minerals. You need minerals to make rocks, but you don't need rocks to make minerals. All rocks are made of minerals. Minerals- A mineral is composed of the same substance throughout.
In geology, rock or stone is a naturally occurring solid aggregate of one or more minerals or mineraloids. For example, the common rock granite is a combination of the quartz, feldspar and biotite minerals. The Earth's outer solid layer, the lithosphere, is made of rock.he types and abundance of minerals in a rock are determined by the manner in which the rock was formed. Many rocks contain silica (SiO 2); a compound of silicon and oxygen that forms 74.3% of the Earth's crust. This material forms crystals with other compounds in the rock.