Minerals

• what two main types of minerals are there?

  silicic and mafic
• there are many properties of minerals that can be investigated to determine what mineral is in a sample:

  -colour

  -streak (determined using a porcelain plate)

  -lustre (amount of reflected light)

  -hardness (measure of resistance to scratching)

  -cleavage (planes created by weaknesses in atomic structure)

  -taste

  -acid test

  -transparency

  -fracture
• what is the 'streak' of a mineral?

  the colour and/or texture of the mineral powder left behind after scraping the mineral across a porcelain plate
• what types of lustre can be seen by different minerals?

  -adamantine (sparkling appearance due to high degree of light reflectance)

  -vitreous (glassy)

  -metallic
• the Moh's ______ measures what?

  hardness
• some different measures of hardness include:

  2.5 --- finger nail

  3.5 --- copper coin

  5.5 --- steel pin

  6.0 --- steel blade

  
  

  7 --- quartz

  10 --- diamond
• what chemical compound in some minerals does the HCl of the acid test react with?

  CaCo3 (calcium carbonate)
• how is density calculated?

  mass (g)/ volume (cm3)
• the fracture refers to the shape of the broken surface of the mineral:

  there are three main types:

  • uneven fractures
  • even / blocky fractures
  • conchoidal fractures (fracture of broken glass)
• the form of a mineral refers to the number and arrangement of crystal faces, and some minerals can display more than one in a single sample

  • prismatic (crystal with regular faces)
  • acicular (fine needle shaped crystals)
  • botryoidal (aggregate like a bunch of grapes)
  • dendritic (branching/tree appearance)
• what atomic structures make up silicate minerals?

  silicon tetrahedra (SiO4)
• what is the overall charge of a single tetrahedra?

  -4
• definition of an ion:

  a charged atom
• the difference between cations and anions:

  cations are positively charged and anions are negatively charged
• this is a __________ structure:

  single tetrahedra

  
• this is a ...

  single chain tetrahedra

  
• this is a ...

  double chain tetrahedra

  
• what structure is made of repeating sheet of these:

  sheet silicates

  
• which silicate structure forms two sets of cleavage planes that intersect at 90 degrees?


  framework silicates