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Colloid vs. Crystalloid: What's the Difference?

Edited by Harlon Moss || By Janet White || Published on January 21, 2024
Colloid is a mixture where small particles are suspended in a medium without dissolving. Crystalloid is a solution where the solute completely dissolves, forming a clear solution.

Key Differences

Colloids are heterogeneous mixtures where particles are dispersed but not dissolved. Crystalloids are homogeneous solutions with solutes that dissolve completely.
In colloids, the suspended particles do not settle out over time. In crystalloids, the dissolved substances remain evenly distributed.
Colloids can scatter light, known as the Tyndall effect, while crystalloids are usually transparent.
The particles in colloids are larger than those in crystalloids but too small to be seen individually.
Colloids are often viscous, whereas crystalloids resemble the viscosity of water.

Comparison Chart

Particle Size

Larger, suspended particles
Smaller, dissolved particles




Particles not visible, scatters light
Transparent, no visible particles

Settling of Particles

Particles do not settle
Particles cannot settle


Milk (colloid)
Saline solution (crystalloid)

Colloid and Crystalloid Definitions


Colloids are stable mixtures where particles do not settle.
Jelly is a colloid with fruit particles suspended.


Crystalloids can pass through a semipermeable membrane.
IV fluids are crystalloids that easily enter blood cells.


Colloids have particles that are intermediate in size.
Fog is a colloid of water droplets in air.


In crystalloids, solutes are ions or small molecules.
Electrolyte drinks are crystalloids restoring body fluids.


A colloid is a mixture with particles dispersed throughout a medium.
Mayonnaise is a colloid of oil in vinegar.


Crystalloids form clear, homogeneous mixtures.
Sugar dissolves in water to form a crystalloid solution.


Colloids display the Tyndall effect when light passes through.
The beam of headlights in fog shows the Tyndall effect.


Crystalloids are often used for hydration or electrolyte balance.
Doctors administer crystalloid solutions for dehydration.


Colloids often have a distinct phase of dispersed particles.
Whipped cream is a colloid with air bubbles dispersed in cream.


A crystalloid is a solution where solutes dissolve completely.
A saline solution is a common crystalloid used in medicine.


A system in which finely divided particles, which are approximately 1 to 1,000 millimicrons in size, are dispersed within a continuous medium in a manner that prevents them from being filtered easily or settled rapidly.


(Chemistry) A substance that can be crystallized.


The particulate matter so dispersed.


(Botany) Any of various minute crystallike particles consisting of protein and found in certain plant cells, especially oily seeds.


Resembling or having properties of a crystal or crystalloid.


(chemistry) Any substance that can be crystallized from solution; a water-soluble crystalline substance that can diffuse through a semipermeable membrane, as opposed to a colloid which cannot.


(botany) One of the microscopic particles resembling crystals, consisting of protein matter, which occur in certain plant cells.


Crystal-like; transparent like crystal, or shaped like a crystal.


Crystal-like; transparent like crystal.


A body which, in solution, diffuses readily through animal membranes, and generally is capable of being crystallized; - opposed to colloid.


One of the microscopic particles resembling crystals, consisting of protein matter, which occur in certain plant cells; - called also protein crystal.


What is a crystalloid?

A solution where the solute is completely dissolved.

Can crystalloids scatter light?

No, they are typically clear and do not scatter light.

How do colloids differ from solutions?

Colloids have larger particles that do not dissolve.

What is an example of a colloid?

Milk is a common example.

Do colloids settle over time?

Generally, they do not settle.

What are crystalloids used for in medicine?

For hydration and electrolyte balance.

Are colloids visible to the naked eye?

The mixture is, but individual particles are not.

What defines a colloid?

A mixture with particles dispersed but not dissolved.

Are crystalloids always liquid?

They can be in any state but are often liquid.

Can colloids be made with gases?

Yes, like foam.

Can colloids be filtered?

Not easily, due to the size of the particles.

Are crystalloids conductive?

Yes, if they contain ions.

How do crystalloids affect blood pressure?

They can increase it by increasing fluid volume.

Do crystalloids have a higher osmolarity than colloids?

It depends on the solute concentration.

Can colloids be separated by centrifugation?

Often, yes.

What's the clinical significance of crystalloids?

They're crucial for patient fluid management.

Do all colloids show the Tyndall effect?

Most do, but not all.

Are colloids or crystalloids better for dehydration?

Crystalloids are typically preferred.

Can colloids be artificially created?

Yes, they are often manufactured.

Is smoke a colloid?

Yes, it's a colloid of solid particles in air.
About Author
Written by
Janet White
Janet White has been an esteemed writer and blogger for Difference Wiki. Holding a Master's degree in Science and Medical Journalism from the prestigious Boston University, she has consistently demonstrated her expertise and passion for her field. When she's not immersed in her work, Janet relishes her time exercising, delving into a good book, and cherishing moments with friends and family.
Edited by
Harlon Moss
Harlon is a seasoned quality moderator and accomplished content writer for Difference Wiki. An alumnus of the prestigious University of California, he earned his degree in Computer Science. Leveraging his academic background, Harlon brings a meticulous and informed perspective to his work, ensuring content accuracy and excellence.

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