Substances that are found naturally in the earth and have a crystalline structure

substances that exist naturally in the earth's crust as single, uncombined elements

geometric structures that are composed of atoms or molecules and have an orderly arrangement

the flat surface of a crystal

a line of powder that can be used to identify a mineral

the way light is reflected from the surface of a mineral

glowing particular colors when exposed to ultraviolet light in a darkened room

minerals that continue to glow for a while after being exposed to ultraviolet light and then placed in the dark 

an alloy of iron and carbon

an alloy of iron, carbon, and nickel or chromium

metals that are valued for their durability, rarity, and beauty

bars of gold that are locked away in guarded vaults as a financial reserve

narrow, vertical underground deposits that resemble the vents of extinct volcanos and contain diamonds

Ruby, sapphire, emerald

the rarest, most durable, and most beautiful minerals that are prized for their hardness, color, and fire (way they reflect light) 

gems that are not as rare, durable, or esteemed that are more easily scratched than more valuable stones

rocks that are formed when magma cools first slowly but is then quickly ejected from the earth before it completely hardens

rocks that are formed when magma cools very rapidly

hard, round structures that form when minerals settle out of water and crystallize around a sand grain 

a horizontal rock layer that has a different type of rock layer above it

deposits of mechanical sediments that may be "glued" together by pressure or chemical action to form sedimentary rock

Rock that consists of smooth pebbles embedded in hardened sand or clay

happen when rocks crystallize and settle out of the water solution

to crystallize

a rock made of at least 50% calcium carbonate

Layered formations usually buried in other sedimentary rock such as sandstone or shale

The upper layers of ground that miners will strip away to reveal the coal underneath it

the change of rock into a new type of rock

the largest group of minerals based on chemical composition

the hardest naturally occurring substance known to man

the number that compares an object's density to the density of water

a term used for any mineral that contains a valuable metallic element

the most abundant metal in the earth's crust 

the two alloys of copper

a metal more valuable than gold or silver

the organic sedimentary rock also known as a fossil fuel

a process of metamorphism caused by stress or movements of the crust