Record 2014/55 | GeoCat 79032 Exploring Minerals and Crystals Teacher notes and student activities Education and Outreach Editor: Katy Tomkins APPLYING GEOSCIENCE TO AUSTRALIA’S MOST IMPORTANT CHALLENGES www.ga.gov.au Exploring Minerals and Crystals Teacher notes and student activities GEOSCIENCE AUSTRALIA RECORD 2014/55 Education and Outreach Editor: Katy Tomkins Department of Industry Minister for Industry: The Hon Ian Macfarlane MP Parliamentary Secretary: The Hon Bob Baldwin MP Secretary: Ms Glenys Beauchamp PSM Geoscience Australia Chief Executive Officer: Dr Chris Pigram This paper is published with the permission of the CEO, Geoscience Australia © Commonwealth of Australia (Geoscience Australia) 2014 With the exception of the Commonwealth Coat of Arms and where otherwise noted, all material in this publication is provided under a Creative Commons Attribution 3.0 Australia Licence. (http://www.creativecommons.org/licenses/by/3.0/au/deed.en) Geoscience Australia has tried to make the information in this product as accurate as possible. However, it does not guarantee that the information is totally accurate or complete. Therefore, you should not solely rely on this information when making a commercial decision. Geoscience Australia is committed to providing web accessible content wherever possible. If you are having difficulties with accessing this document please email [email protected]. ISSN 2201-702X (PDF) ISBN 978-1-925124-50-7 (PDF) GeoCat 79032 Acknowledgements Original concept and content compiled by Julie M Gunther (1996): Exploring Crystals. Scientific advice and editing by Alan Whitaker, Anthony Senior, John Pugh, Terry Mernagh, Ian Roach and Science ASSIST Educational advice by Shona Blewett, Lara Davis, Steve Tatham and editing by Vicki Pow and Jeanette Holland. Graphics, design and production by Products and Promotion, Geoscience Australia Cover images: (LHS) Geoscience Australia, photo credit: Katy Tomkins. (top RHS) Wikimedia Commons, photo credit: Alexander Van Driessche. (bottom LHS) Wikimedia Commons, photo credit: Rob Lavinsky. (bottom middle) Geoscience Australia, photo credit: Chris Fitzgerald. (bottom RHS) Wikimedia Commons, photo credit: Rob Lavinsky. Education Centre Geoscience Australia GPO Box 378, CANBERRA ACT 2601. Phone: +61 2 6249 9673 Fax: +61 2 6249 9926 Email: [email protected] Bibliographic reference: Geoscience Australia, 2014. Exploring Minerals and Crystals: Teacher Notes and Student Activities. Record 2014/55. Geoscience Australia: Canberra. http://dx.doi.org/10.11636/Record.2014.055 Contents 1 Introduction ............................................................................................................................................ 1 1.1 Student activities .............................................................................................................................. 1 2 Rocks and minerals in history ............................................................................................................... 2 3 Minerals, crystals and rocks – what’s the difference? ........................................................................... 3 3.1 How do crystals form? ..................................................................................................................... 5 3.2 Extension: Fractional crystallisation ................................................................................................. 7 4 Identifying minerals ................................................................................................................................ 8 4.1 Colour and streak ............................................................................................................................. 8 4.2 Lustre ............................................................................................................................................... 9 4.3 Hardness ........................................................................................................................................10 4.4 Crystal shape .................................................................................................................................13 4.5 Cleavage ........................................................................................................................................13 4.6 Specific gravity ...............................................................................................................................14 4.7 Habit (natural shape) .....................................................................................................................14 4.8 Extension: Crystal systems ............................................................................................................17 5 Using crystals in Earth Science ...........................................................................................................18 5.1 Geoscience Australia .....................................................................................................................18 6 Mesmerising minerals ..........................................................................................................................20 6.1 Calcite ............................................................................................................................................20 6.2 Quartz ............................................................................................................................................20 6.3 Feldspar .........................................................................................................................................21 6.4 Gypsum ..........................................................................................................................................21 6.5 Pyrite ..............................................................................................................................................22 6.6 Magnetite .......................................................................................................................................22 7 Captivating crystals .............................................................................................................................23 7.1 Geodes...........................................................................................................................................23 7.2 Metallic crystals ..............................................................................................................................23 7.3 Cultivated crystals ..........................................................................................................................24 7.4 Glass ..............................................................................................................................................24 7.5 Luminescent crystals .....................................................................................................................24 7.6 Irradiated crystals ...........................................................................................................................25 7.7 Electric crystals ..............................................................................................................................25 7.8 Pseudomorphs ...............................................................................................................................25 7.9 Solar cells.......................................................................................................................................25 8 Gemstones ..........................................................................................................................................27 8.1 Definition ........................................................................................................................................27 8.2 The 4 C's ........................................................................................................................................28 8.2.1 Clarity .......................................................................................................................................28 8.2.2 Colour .......................................................................................................................................28 8.2.3 Cut ............................................................................................................................................28 8.2.4 Carat .........................................................................................................................................29 Exploring Minerals and Crystals iii 8.3 Australian mineral and gemstone resources .................................................................................30 8.4 Famous gemstones .......................................................................................................................31 8.4.1 Diamonds .................................................................................................................................31 8.4.2 Opals ........................................................................................................................................31 8.4.3 Sapphire ...................................................................................................................................33 8.4.4 Ruby .........................................................................................................................................33