i have 2 quartz crystal that r about 7 pounds each
Quartz is very resistant to weathering. It sounds like you may have calcite. If you have hydrochloric acid, and put a drop on your rock sample and it fizzes, it's likely calcite. I've never tried vinegar, it may fizz? Can you describe the shape of the crystal? i.e. square, rectangle, polygon, pointed tip... Does it scratch glass? How does it break? ie. Jagged edges? Smooth face? Round half circles like some broken glass does?
