GOLD Glossary

alloy

A mixture of two elements, at least one of which is a metal, which form a new metal with desired properties.

atom

The smallest unit of an element that retains its properties.

conductivity

The ability of a mineral to transmit heat, electricity, or sound.

compound

A naturally-occurring combination of two or more elements in a specific ratio. Compounds need a chemical change to separate into their constituent parts.

corrosion

Gradual chemical destruction of a mineral. Corrosion often, but not always, operates through oxidation. Tarnish is a form of corrosion.

crystal

A unit of a mineral that has a symmetrical shape with flat, angled surfaces. The shape arises from an orderly arrangement of the mineral's atoms. Crystals can aggregate to form distinctive overall shapes.

density

The average mass per unit volume of a substance.deposit (mineral)A natural concentration of a mineral in Earth's crust.

ductility

The ability of a mineral to be pulled into wire.

element (chemical)

A substance that cannot be broken down into simpler substances by chemical means. Elements are composed of a single kind of atom.

fineness

A measure of the amount of pure gold in a metal, in parts per thousand.

gold standard

A system in which currency can be redeemed for a fixed amount of gold. The bank or government must have enough gold in reserve to redeem all its circulating currency.

karat

A measure of the amount of pure gold in a metal. One karat is 1/24th of the total weight of the object. 100 percent pure gold is 24 karats.lusterThe manner in which a mineral reflects light.

hardness

A measure of how hard or soft a mineral is relative to diamond, the hardest mineral on the 10-point Mohs scale of hardness.

hydrothermal fluids

Hot water, steam, and gases trapped in fractured or porous rocks underneath Earth's surface.

malleability

A mineral's ability to be hammered into thin sheets.

mass

A measure of the total amount of matter in a body.

metal

A class of elements that have characteristic physical properties. Metals are generally good conductors, and are reflective, malleable, and ductile.

mineral

A solid substance with a crystal structure that formed via geologic processes. Minerals can be either elements or compounds.

mixture

A combination of two substances that can be separated by a physical change.

native element

The pure or nearly pure form of an element found in nature.

nugget

A lump of gold found in nature.

ore

Rock from which valuable minerals can be extracted.

oxidation

To become chemically combined with oxygen.

placer

A deposit of valuable minerals in a lake-, river-, or seabed.

rock

Any naturally occurring combination of one or more minerals.

tarnish

To dull the luster of a mineral by exposure to air or dirt. Tarnish is a form of corrosion.

vein

A mineral deposit in a fracture in the Earth.

volume

The amount of space occupied by a three-dimensional object or region of space.