Gypsum is not a metal.
It’s a common evaporite-derived non-metal mineral with deposits located throughout the world.
Here, we’ll provide you with a complete guide to gypsum, including how it originated, what makes it a non-metal, and some common uses of it.
Is Gypsum a Metal? (EXPLAINED)
What is Gypsum?
Millions of years ago, saltwater invaded the Michigan Basin at least six times.
As the seas evaporated, rock and mineral deposits were left behind, such as halite, gypsum, clay, sandstone, and coal.
The fifth of the six invasions (now known as the Mississippi River) caused Michigan’s gypsum deposits, some of the world’s most prosperous.
Most gypsum in the United States comes from the open-pit mines west of the Mississippi River.
Gypsum is a common non-metallic mineral composed of calcium sulfate (CaSO4) and water (H2O).
Its chemical name is calcium sulfate dihydrate (CaSO4.2H2O).
Mined from sedimentary rock formations, the mineral forms as crystals that can often be found projecting from rock.
This formation is due to the water that makes up the mineral, known as ” water of crystallization.”
In this way, you can easily compare the formation to ice.
However, unlike ice, gypsum doesn’t change its state until it reaches 212 degrees Fahrenheit.
And when it does change, the water of crystallization becomes water vapor and is driven off of the gypsum, similar to how steam is driven off of water.
In pure form, gypsum is white.
However, gypsum typically contains impurities that make the rock appear gray, brown, pink, or almost black.
See also: Can Gypsum Scratch Glass?
Metal vs. Non-Metal Mineral
Minerals are divided into two major categories: metal and non-metal.
Metal minerals include copper, lead, zinc, iron, and nickel.
Non-metal minerals include sand, clay, gypsum, and quartz.
About 75% of the elements on the periodic table are metals.
Most metals are easy to recognize by their shiny, metallic appearance.
Here are some physical and chemical properties that can identify metal minerals.
Metal Physical Properties
- Good conductors of heat and electricity.
- High melting point.
- High density.
- Usually solid at room temperature.
- Opaque as a thin sheet.
Metal Chemical Properties
- Outer shell has one to three electrons.
- Corrode easily.
- Lose electrons easily.
- Form basic oxides.
- Low electronegativity values.
- Good reducing agents.
Nonmetals include the non-metal, halogen, and noble-gas groups on the periodic table.
They are a diverse collection of elements.
Here are some physical and chemical properties that can identify non-metal minerals.
Nonmetal Physical Properties
- Dull appearance (sometimes colorless).
- Poor conductors of heat and electricity.
- Non-ductile solids.
- Brittle solids.
- Can be solids, liquids, or gases at room temperature.
- Transparent as a thin sheet.
- Not sonorous
Nonmetal Chemical Properties
- Outer shell has four to eight electrons.
- Readily gain or share valence electrons.
- Form acidic oxides.
- High electro-negativities
- Good oxidizing agents
What Makes Gypsum a Non-Metal?
Gypsum’s distinguishing properties that make it a non-metal are that it’s usually clear or white, has one perfect cleavage (may show up to 3 cleavages), and it’s easily scratched with a fingernail.
The following are some of gypsum’s other important chemical and physical properties that signify it’s not a metal.
- Chemical composition: Hydrous Calcium Sulfate, CaSO4.2H2O
- Crystal system: Monoclinic
- Mohs hardness: 2
- Specific gravity: 2.2
- Color: Colorless, red, brown, clear, yellow, white, grey
- Diagnostic properties: Specific gravity, cleavage, low hardness
- Diaphanous property: Transparent to translucent
- Texture: Silky, sugary, and/or vitreous
- Cleavage: Perfect
Common Uses for Gypsum
In the United States, the vast majority of gypsum is used to manufacture construction products, like wallboard (also known as drywall, rock lath, Sheetrock, Gibraltar Board, gypsum-board, and Gyproc) and plaster products.
The mineral is a primary product in these products because of its widespread availability, low cost, and fire-retardant properties.
Gypsum is also used prominently as a hardening retainer in the production of cement.
It’s even great for agricultural applications, where it acts as a soil amendment, a conditioner, and a fertilizer.
Smaller quantities of pure gypsum are used in metal smelting and glassmaking.
Varieties of gypsum known as “satin spar” and “alabaster” are used for ornamental purposes; however, their low hardness levels decrease the durability of such products.
Fun Facts About Gypsum
- Smugglers have used gypsum to make a variety of objects, including hollow statues and figurines, to evade the scrutiny of customs inspectors.
- 80% of gypsum is sold and consumed in countries where it’s produced due to its high weight, low cost, and widespread availability.
- After the London Fire of 1666, the King of France required all construction to be done with gypsum due to its fire-retardant properties, which became known as the “Plaster of Paris.”
There’s our guide to gypsum. Now you know what it is, why it’s not a metal mineral, and much more.