Mineralogy Midterm Prep Flashcards
(170 cards)
what is a mineral
MINERAL is a naturally occurring inorganic solid with a definite chemical composition & an ordered crystalline structure
Idiochromatic
The color of the mineral seldom varies, and is diagnostic.
Allochromatic
Color varies due to impurities or viewing angle
Chromophores
Elements with strong pigmenting capabilities
zoning
While a mineral is growing, environmental changes occur which produce different “chemical zones”.
What colors emrald (beryl) and ruby (corrundum)
Cr+3
Frenkel Defect?
Negative ion missing from structure, creating a site which will attract and trap any free electron; ELECTRON COLOR CENTER (F-Center)
Amethyst Color?
Iron containing quartz is exposed to gamma radiation from potassium 40 decay. (ENERGY OXIDIZES Fe3+ to Fe4+)
Color of smokey quartz?
radiation damage (of AlO4 group)- Al substitution for Si
Color in blue calcite?
shearing stress followed by radiation
Color in Quartz variety Chrysoprase?
chlorite impurities or mixture of nickel minerals
Color in Milky Quartz?
water inclusions
Blue Quartz?
Rutile inclusions (Tio2)
Opalescense?
optical affect from light bouncing off of microscopic spheres of silica spheres
Mohs Hardness Scale
Talc, Gypsum, Calcite, Flourite, Apatite, Orthoclase, Quartz, Topaz, Corundum, Diamond
define pseudomorph
different atomic structure; same crystal form
define polymorph
same chemical composition; change in crystal form (ex: diamond- graphite)
X-Ray Diffraction (XRD) tells you…
atomic structure (structural fingerprint)
electron microscopy energy dispersive xray flourescence for…
chemical analysis (chemical fingerprint)
what is the coloring agent of sapphire
Fe3+
color is a result of…
absorption, our eye blends the transmitted colors into a single color
where do diamonds occur
occurs in mantle derived kimberlite pipes along with other high temp/ high pressure inerals (the pipe picks up diamonds which formed in the mantle and rapidly carries them to the surface)
top 2 counties for diamond production…
botswana, russian federation
Where are pink diamonds from?
argyle mine, australia