What Is Holy Basil? Holy basil, sometimes called Thai basil tulsi, is an herb from the same family as the basil often used in cooking. Although it's used in Ayurvedic medicine, clinical studies backing up any of the traditional uses for this herb are limited.
Pure diamond is the hardest known natural mineral substance and will scratch any other natural material. Diamond is therefore used to cut other diamonds; in particular, higher-grade diamonds are used to cut lower-grade diamonds. But after billions of bucks in research, times have moved on.
Best Answer: Well, the hardest mineral on earth is a diamond. For rocks, which are made up of one or more minerals, the hardest are those which contain quartz. There is no single hardest rock but some of the rocks that would be very hard and strong and well-cemented quartz sandstones (a sedimentary rock), quartzite (a metamorphic rock formed from quartz sandstone) and granites or rhyolites (both igneous rocks with a lot of quartz).