A Review of Basic Gemstone Introductions & Definitions By Brandon Milner Edited/Enhanced by Susie Aber
Getting Started! Come to class &… Online Syllabus with links to lectures http://academic.emporia.edu/abersusa/go340/syllabus.htm Final Course Project http://academic.emporia.edu/abersusa/go340/webpage.htm
Gem Quiz http://academic.emporia.edu/abersusa/go340/gemquiz.htm Gem Definitions & History http://academic.emporia.edu/abersusa/go340/define.htm Gem Briefs http://academic.emporia.edu/abersusa/go340/gembrief.htm
Gemology/Gemstones • Gemstone: Stones that are for personal use and desired for beauty, rarity, durability, and stability. • Only 70 minerals are classed as gemstones; 20 of these are common.
• Gemology: Science of gems based on Chemistry/Physics/Geology.
Mineralogy/Mineral • Mineralogy: Study of minerals based on crystalline structure, chemical composition, origin, occurrence and associations. • Mineral Characteristics: • Naturally Occurring • Homogenous • Solid • Fixed Chemical Composition • Fixed Crystalline Structure • Inorganic
Mineralogy/Mineral Cont. • • • •
Natural: Not made in a lab. Homogenous: Is the same throughout. Solid: No liquid or gas phases. Defined Chemical Composition/Crystalline Structure: Fixed composition/geometric pattern. • Inorganic: Made by chemical/geological processes. • Mineraloid: Mineral that lacks part of these qualifications.
Gemology/Gemstones Terminolgy • Beauty: Color, Luster, Transparency, cutting properties. • Durability: Resistance to scratching and breaking. • Tenacity: Resistance to breaking. • Hardness: Resistance to scratching. • Stability: Ability to retain original color and properties.
Basic Value & Grade Figure right taken from Barbara Smigel (2008) www.bwsmigel.info/Lessons1and2/DEBasicTerms.html
• Rarity: Limited supplies can raise price and demand. Higher demand can help to find new discoveries. • Demand or Fad: Prices depend on what current fads or fashions are currently in style. • Portability: Prices are high based on the size of the gemstones relative to other objects.
Gem Naming/Classification • Divide gems as diamonds and colored stones NOT precious and semiprecious stones. • Gemstones named from: Color, Origin, Properties, Characteristics, People, Special names to promote although sometimes misleading. • New gemstones must be authorized by Commission on New Mineral Names of the International Mineral Association.
Gemstone Classification • Inorganic Types • Groups: Similar Properties/Structures. • Species: Similar Structures/Compositions. • Variety: Similar Colors/Optical Properties. Examples-color, transparency, refraction.
• Organic Types • Chemical Compositions: This would include gems such as Jet or Ivory.
Synthetics/Imitations • First started in 1800’s due to high demand. • Examples include Diamond, Spinel and Opal.
• Synthetic: Made to have identical properties of real gem. • Imitation: Made to look like the real gem without identical properties.
Basic History of Formal Gem Education • Gemstones course first taught at a Colorado university in 1909. • Gemological Society of America founded in 1930 by Robert Shipley. • GIA offers courses in gem/bead identification, value, designing and sales. • GIA is a non-profit organization based on money from public services and publications. • Plentiful educational opportunities concerning gemstones.
References & Links! Aber, S. 2011. Some Basic Definitions and History. http://academic.emporia.edu/abersusa/go340/define.htm Gemological Institute of America. http://www.gia.edu/ Lewton-Brain, C. 1993. On Jewellery Career Options. http://www.ganoksin.com/borisat/nenam/career.htm Olson, D. W. 2002. An Overview of Production of Specific US Gemstones. US Bureau of Mines Special Publication 14-95. http://minerals.er.usgs.gov/minerals/pubs/commodity/gemstones/sp1495/index.html Synthetic & Simulant http://minerals.usgs.gov/minerals/pubs/commodity/gemstones/sp1495/synthetic.html Rock & Mineral Collecting http://pubs.usgs.gov/gip/collect1/collectgip.html Natural Gemstones http://pubs.usgs.gov/gip/gemstones/ Annual Gemstone Production http://minerals.usgs.gov/minerals/pubs/commodity/gemstones/ In 2011- http://minerals.usgs.gov/minerals/pubs/commodity/gemstones/mcs2011-gemst.pdf