How can we help?

You can also find more resources in our Help Center.

16 terms

What do the terms mean?

STUDY
PLAY
Aphanitic
cyrstals too small to see easily without a magnifying glass
Bioclastic
formed from living organisms (shells) settling out of water
Chemical precipitate
material forming directly out of dissolved materials in water (like making rock candy)
Clastic or detrital
formed from materials settling out of water
Eolian
formed from wind sediments
Extrusive
form outside of the earth's crust or just barely under- cooling rapidly
Fissile
refers to sedimentary rocks that easily split into layers (shales)
Fluvial
formed in river beds
Foliated
appears to be layers of crystalline rock- term used for metamorphic rocks only
intrusive
formed inside of the earths crust, plutons are intrusive, cool slowly
lacustrine
formed in lakes
Mafic
high in ferromagnesium silicates (olivine, biotite, hornblend)
Phaneritic
having easily visible crystals
plutonic
rock formed from magma that penetrated other rocks- dikes, sills, batholiths
Sialic
high in non-ferromagnesium silicates (feldspars, muscovite, quartz)
Vesicular
has vesicles (holes) which are apparent