Describe how to distinguish between a mineral with a hardness of 6 and one with a hardness of 4 using only a glass plate and a copper penny?

If molecules are made of atoms.And molecules are use in chemical reaction to make new elements. Does the elements in atoms also changes? What is the furthest anyone has dug to the earths core? What boundary allows magma to rise to the surface to make new crust? Parts of red blood cells? What gem is found in the gravel of riverbeds? Is Paris north or south of tropic of cancer or equator? Why do natural body joints last longer than artificial joints? What does the dotted line mean in the map represent? What is the Crystal size of lava? What is the average frequency of human? The substance dissolved in a solution is the? What is the mixture called when crude oil and petroleum come straight from the ground? What type of stimulis is it when endocrine organs are prodded into action by other hormones? Why are there glaciers in warm countries like Chile? What is the meaning of pointed finger? Is there any herb or plant that helps to keep scorpions away? Which is largest country through which the equator passes? Is Ceres the only planet with a ice mantle? What is the differentiation of fauna and flora? Is iodine molecule an organic molecule?