1. DiamondsDiamonds J.D. Price

2. Images and much of the information here is from the American Museum of Natural History Diamond Exhibit, by Dr. George Harlow http://www.amnh.org

3. Habit – a common natural growth geometry Trigons – the building blocks of a diamond Form

4. Image from Pauling, 1970 Diamond Graphite Q: What element is represented by each sphere?

5. Graphite - steep changes in energy for changes in pressure (dG/dP) Diamond - higher G at low pressure, but shallow dG/dP G is energy The carbon system

6. At P = 5 kbar

7. Carbon phase diagram

8. Diamond origins Examples of likely depths and origins for South African diamond deposits. Diamonds are formed in regions of the mantle at sufficiently high pressure. Diamonds may originate from even deeper sources in the mantle

9. This volcanic structure is a diatreme The only locality to let you dig for your own diamonds: Crater of Diamonds State Park, Arkansas Diatreme

10. White dwarf BPM 3793 0.6 size of the earth White dwarves are burned-out sun- sized stars Core is carbon, formed as the end product of fusion Metalfe et al, 2004 concluded from astroseismic measurements that it is 90% solid (5 E 29 kg or 1 E 34 Carats) Diamonds in space

11. Diamonds were first discovered in India around 500 B.C. These were first weighed relative to the weight of a seed from the seed pod of the carob tree. 1 ct = 200 mg Carat

12. Modern diamond production

13. Ruby (Corundum) Sapphire (Corundum) Emerald (Beryl) Peridot (Olivine) Other Gems

14. Chrysoberyl BeAl 2 O 4 Cat’s eye Needle-like inclusions reflect light. Also seen in tourmalines, scapolite, corundum, spinel and quartz but these must be designated as "tourmaline cat's eye", or "ruby cat's eye". Alexandrite Extreme pleochroism - goes from green- blue to purple depending on the angle of stone. Gemmy crystals Brown to green gemmy crystals found in pegmatite with corundum and beryl.

15. Painite 6/m CaZrB(Al 9 O 18 ) - Ca 0.77 Na 0.19 Al 8.8 Ti 0.19 Cr 0.03 Zr 0.04 B 1.06 O 18 As of 2005, there were only twenty-five known specimens - now 1000’s Painite #12 Rare mineral from Ohngaing, Mogok district, Myanmar (Burma). Painite #5 Painite #6 See http://minerals.gps.caltech.edu/FILES/Visible/painite/Index.html for current info on painite discoveries.http://minerals.gps.caltech.edu/FILES/Visible/painite/Index.html

16. Serendibite _ 1 Ca 2 (Mg,Al) 6 (Si,Al,B) 6 O 20 - Ca 2 Mg 4.5 Al 1.5 Si 3.6 Al 1.8 B 0.6 O 20 Rare mineral from Gangapitiya near Ambakotte, Ceylon Recently sold for about $14,300.00 per carat

17. Benitoite Nearby King City Asbestos Mine - Superfund site for serpentine asbestos Santa Rita Peak, San Benito, CA. Peridotite (source) is sparsely vegetated _ 6 m2 BaTiSi 3 O 9 Rare, deep blue-stone found only in California. Strongly fluorescent! Gem quality crystals even rarer. Small faceted stones are $500 - $3000 per carat 1.67 carats, $4,175 Africagems.com

18. Archon – 3.7 to 2.5 Ga, Proton – 2.5 -0.5 Ga, Tecton - younger Diamondiferous material hosts

19. 1.Cullinan - 3,106.75 carats - 1905, South Africa 2.Excelsior - 995.20ct. - 1893, South Africa 3.Star of Sierra Leone - 968.80ct. - 1972, Sierra Leone 4.Zale - 890.00ct. - 1984, Africa 5.Great Mogul - 787.50ct. - 1650, India 6.Woyie River - 770.00ct. - 1945, Sierra Leone 7.Presidente Vargas - 726.60ct. - 1938, Brazil 8.Jonker - 726.00ct. - 1934, South Africa 9.Reitz - 650.80ct. - 1895, South Africa 10.Unnamed - 620.14ct. - 1984, South Africa 3K carats = 600 g = 1.3 lbs Largest Uncut Stones

20. The big hole, Kimberly, SA Mirny, Siberia d=525m Ekati, NWT Mining

21. Separating

22. Abrasion (stone cutting, polishing) Jewelry Experimentation Uses for diamond

23. Gem stones are valued by four basic criteria 1.Color 2.Cut 3.Clarity 4.Carat weight If you ever decide to seriously buy a gem stone – get a 10x or better hand lens! #1 rule: in most cases you get what you pay for. 4C’s

24. Color is an important factor in the purchase of a diamond and can affect the price by 2- 10% per letter* Color

25. Colored stones are not popular in the US, but are heavily marketed in South America and Europe “Fancy diamonds”

26. Cut refers to shape, but its not necessarily the style that influences diamond cost Cut

27. Cutting

28. Cut is so important to the value of a diamond that it can affect the value by 25% to over 50%. Cut: the behavior of light A missed cut sends makes light reflect, and diamond loses brilliance A perfect cut sends makes light refract to the table, and diamond gains brilliance

29. Clarity is a rarity factor that affects diamond value by 5 - 20% for each increment on the AGS diamond grading scale. In most diamonds purchased by consumers, the diamond has few to no features noticeable to the unaided eye. Clarity

30. In the early 1900's the Metric Carat was established. 1 Carat = 0.2 gram Full Carat: A diamond that weighs or rounds to 1.00 Carat. Light Carat: A diamond that weighs slightly less than 1.00 Carat. Example.96 -.00. This IS NOT a full Carat. Diamonds in this range are priced less. Magic Sizes: Diamonds that weigh-in exactly at or greater than a major size category. Each major size category marks a greater degree of rarity, and commands a higher price. Q: which of the four c’s are nature’s doing, and which are the gemologist’s doing? Carat

31. Today industrial (small unclear) diamonds are readily synthesized – gem quality is a little more difficult An early GE diamond making press Synthesis

33. Gemisis Lifegem Apollo Diamondview Spectrometer (tool to separate out synthetics) Adia Not pictured Tairus - Russian NAS and Thai venture

34. Moissanite SiC Similar refractive properties Very hard (but not as hard as diamond) Absorbs more UV radiation Not combustible Q: Why the similar structure for diamond and moissanite (hint: look at the periodic table)? Substitutes

35. Cubic Zirconia ZrO Similar refractive properties Hard (but not as hard as diamond) – rounded points Not as conductive Not combustible Q: What is non-scientific amount the cut stone diamond market (if a CZ or Moissonite gives the same brilliance, then why are diamonds so expensive)?