<span>First, you should know that the four properties given are used in the identification of minerals. Hardness is the level of difficulty with which the smooth surface of a mineral sample may be scratched. Cleavage is how the crystal splits along a plane. Color is the result of the reflection of the light by the atoms and Streak is the color displayed by the mineral when it is crushed to a fine powder, while impurity contents affect the color, they do not affect the streak. So, streak is a better technique to identify minerals than colors. And the other two, hardness and cleavage are well known as being very useful. So, the least useful is color. Answer: option D.) color.</span>
The density is defined as mass of a substance per unit of its volume
It can be expressed in different units like g/L g/m3 Kg/dm3 etc
We are given that
mass of substance = 27.3 grams
volume of substance = 7 cm^3
the density = Mass of substance / volume of substance
density = 27.3g / 7 cm^3 = 3.9 g /cm^3