Limestone is by definition a rock that contains at least 50% calcium carbonate in the form of calcite by weight. All limestones contain at least a few percent other materials. These can be small particles of quartz, feldspar, clay minerals, pyrite, siderite and other minerals.
Answers (4) You have not mentioned the name of the medicine in your post. Ideally 4 times a day means every 6 hours. It depends on what the medicine is as to how rigid you should be in regards to dosing. If the medicine is an antibiotic then every 6 hour dosing is important as is pain relief medication if in severe pain. If the dosing isn't so critical then 4 times a day could be evenly spaced out during the waking hours.
Medications administered more frequently than daily but not more frequently than every 4 hours (e.g., BID, TID, q4h, q6h) Administer these medications plus or minus 1 hour from the scheduled time. Medications administered more frequently than every 4 hours (e.g., q1h, q2h, q3h) Administer these medications within 25% of the dosing interval (e.g., plus or minus 15 minutes for hourly doses, plus or minus 30 minutes for every 2 hours dosing, plus or minus 45 minutes for every 3 hours dosing).