text: 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.\n\nAs 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).\n\nSo 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.\n\nEDIT: OK, found an online table. Rose Quartz has a hardness of 7, specific gravity of 2.65, shows conchoidal fractures.\n\nSo that would be my guess. Rose Quartz.