Hardness Scale on Pitara Kids Networkhttps://www.pitara.com/tags/hardness-scale/Recent content in Hardness Scale on Pitara Kids NetworkHugoen-usSat, 13 Jun 2026 21:46:31 +0530Minerals are graded according to their hardness, on a scale from 1 to 10. T...https://www.pitara.com/non-fiction-for-kids/did-you-know-for-kids/minerals-are-graded-according-to-their-hardness/Sun, 29 Aug 2004 18:53:43 +0000https://www.pitara.com/non-fiction-for-kids/did-you-know-for-kids/minerals-are-graded-according-to-their-hardness/