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.
Diamond is an allotrope of carbon. It is the hardest known natural material and the third-hardest known material after aggregated diamond nanorods and ultrahard fullerite. Its hardness and high dispersion of light make it useful for industrial applications and jewelry.
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).