1 / 7

Mohs Scale of Hardness

Mohs Scale of Hardness. Mohs Scale History. Mohs scale was devised by Friedrich Mohs in 1812 You use Mohs scale by testing your unknown mineral against these known minerals. The known minerals are: 1. Talc 6. Orthoclase (Feldspar) 2. Gypsum 7. Quartz

hanne
Download Presentation

Mohs Scale of Hardness

An Image/Link below is provided (as is) to download presentation Download Policy: Content on the Website is provided to you AS IS for your information and personal use and may not be sold / licensed / shared on other websites without getting consent from its author. Content is provided to you AS IS for your information and personal use only. Download presentation by click this link. While downloading, if for some reason you are not able to download a presentation, the publisher may have deleted the file from their server. During download, if you can't get a presentation, the file might be deleted by the publisher.

E N D

Presentation Transcript

  1. Mohs Scale of Hardness

  2. Mohs Scale History • Mohs scale was devised by Friedrich Mohs in 1812 • You use Mohs scale by testing your unknown mineral against these known minerals. • The known minerals are: • 1. Talc 6. Orthoclase (Feldspar) • 2. Gypsum 7. Quartz • 3. Calcite 8. Topaz • 4. Flourite 9. Corundum • 5. Apatite 10. Diamond

  3. Comparing Hardness • Whichever mineral scratches the other mineral is harder. • If they both scratch each other, they are the same hardness.

  4. Handy Objects • There are a few handy objects that also fit in the Mohs scale. • A fingernail is between 2 and 3. • A copper strip or penny is just under 3. • A knife blade or bar magnet is 5 to 5.5. • Window glass is 5.5 to 6. • Porcelain streak plate is 6.5 to 7. Ex. If the mineral can scratch the porcelain plate the mineral is harder than 7. If the porcelain streak plate can scratch the mineral, then the mineral is softer than 7.

  5. Hints for Using the Scale • A larger specimen will be softer than smaller crystal specimens. • Some minerals will have a range of hardness due to impurities. • Don’t be fooled by a dust trail on a mineral. It may be the mineral that you scratched the new mineral with that left some behind. • Remember this phrase to remember the minerals on the Mohs Scale: • The Geologist Can Find An Ordinary Quartz, (that) Tourists Call Diamond!

  6. If your mineral can…. Can be rubbed off with your fingers ……1 Can be scratched with your fingernails ..2 Can be scratched with a penny……….3 Can easily be scratched with a butter knife …4 Is hard to scratch with a butter knife ….5 Can be scratched with a steel nail but not glass ….6 Can be used to scratch glass or a porcelain plate …..7 Can scratch topaz …..8 Can scratch corundum ……9 Can scratch diamond …….. 10

  7. Moh’s Mini Lab • There are nine minerals around the room. Your group will grab a mineral kit and you will move around the room testing the hardness of each mineral. • When you have the minerals hardness determined, get the actual mineral names from the teacher. • Check online for the actual mineral hardness and answer the questions.

More Related