text: sorry i'm stuck again can someone please help me? a rose colored mineral specimen is given to you for identification.  it has a conchoidal freacture, no streak, and a non-metallic luster.  it can be scratched with a steel file, but not with glass or a pocketknife blade.  it has no streak.  its mass is 53 grams. you place it in water and it displaces a volume of 20 cubic centimeters of water. i have a moh's hardness scale and a list of specific gravity of minerals but i still don't understand it. (a)what is the hardness of this mineral? explain your answer to me please. (b) what is the specific gravity of this mineral and could you show me your calculations so i can use them for my next problem.  (c) using all these properties, identify this mineral. please help me i thnk i got in over my head on this physics class. any help is greatly appreaciated. thanks so much!~sterbenator~ starting with hardness.. a steel knife is a bit over 5 and glass about 5.5, a steel file (hardened steel) can be as high as 6.5. so i would guess that whatever you have has a hardness between 5.5 and 6.5.  as far as density, consider the mass and volume (displacement). 53 grams / 20 cm^3 means it has a density of 2.65g/cm^3 (note, g/cm^3 is the same as specific gravity).  so what mineral has a hardness between 5.5 and 6.5 and a specific gravity of 2.65? well, i don't have a minerals table in front of me, but those are the key numbers you need. if no one else answers, i'll look it up tonight.  edit: ok, found an online table. rose quartz has a hardness of 7, specific gravity of 2.65, shows conchoidal fractures.  so that would be my guess. rose quartz.