animated with text reading: hardness - 1. talc, 2. gypsum, 3. calcite, 4. fluorite, 5. apatite, 6. feldspare, 7. quartz, 8. topaz, 9. corundum, 10.... - 剛玉 個影片檔及 b 捲影像00:08
hardness - 1. talc, 2. gypsum, 3. calcite, 4. fluorite, 5. apatite, 6. feldspare, 7. quartz, 8. topaz, 9. corundum, 10. diamond - 剛玉 個影片檔及 b 捲影像00:14