Minerals Flashcards
(98 cards)
About how many known minerals are there?
~3500
How many minerals are reasonably common?
~200
How many minerals account for most of the earth’s crust?
~20
What class of mineral makes up 94% of the crust?
silicate minerals
What are minerals in the crust limited by?
the elements available and silicate mineral structure
What 5 properties must a substance meet to be considered a mineral?
naturally-occurring, inorganic, crystalline solid, definite chemical composition, characteristic physical properties
What are a mineral’s physical properties determined by?
chemical composition and crystal structure
What are ionic bonds?
electromagnetic attraction
What mineral contains ionic bonds?
halite (table salt)
Why are ionic bonds brittle?
when cracked, negative and positive ions repel and push each other away
What type of bond involves metal ions “floating” in an electron sea?
metallic bonds
How do metallic bonds behave?
plastic
What are covalent bonds?
sharing of electrons
What is the composition of most silicate bonds?
50:50 covalent:ionic
What does the composition of silicate bonds indicate about their behaviour?
behave elastically but break in brittle manner
How do covalent bonds behave?
elastic and flexible
What is crystal structure?
arrangement of atoms in a regularly repeating, orderly pattern
What is a crystal?
homogeneous solid bounded by naturally-formed planar surfaces
What are planar surfaces?
external expression of internal ordering of atoms
What does the internal ordering of atoms in a crystal result in?
specific angular relationships
What bonds determine crystal structure?
strongest bonds
What bonds determine crystal strength?
weakest bonds
What are 5 ways in which minerals can form?
solidification of a melt, precipitation from solution, solid state diffusion, biomineralization, precipitation from gas
What is an anhedral?
mineral without well-formed crystal faces