TLDR: Friability is a property of materials that easily break into smaller pieces when rubbed or under pressure. It can apply to substances like asbestos or silica that can become airborne and pose a health hazard. It can also describe softer rocks that easily crumble, as well as tumors that are easily torn apart. In the pharmaceutical industry, friability testing is used to check the durability of tablets during transit.

Friability is a term used in materials science to describe how easily a solid substance can break into smaller pieces when it is rubbed or under pressure. Imagine if you had a piece of clay and you accidentally brushed up against it, causing it to crumble into smaller bits. That's an example of friability. The opposite of friable is indurate, which means the substance is tougher and doesn't break easily.

Some substances, like asbestos or crystalline silica, are considered friable because they can easily release small particles into the air when disturbed. These particles can then be inhaled and pose a health risk. Other substances, like concrete, can be mechanically ground down into fine dust, but they are not generally considered friable because it takes a lot of effort to break them apart.

In geology, friable and indurated are terms used to describe how well the components of soft rocks, like sandstones or mudstones, are held together. If the rock fragments easily crumble, it is considered friable. Examples of friable geological substances include clumps of dried clay or chalk.

In medicine, the term friable is used to describe tumors that are easily torn apart. This is an important determination because tumors that are friable have a higher risk of being malignant and spreading to other parts of the body. Examples of friable tumors include certain types of cancer and an inflamed gallbladder.

In the pharmaceutical industry, friability testing is a laboratory technique used to test the durability of tablets during transit. Tablets are repeatedly dropped over a fixed time using a rotating wheel, and the result is inspected for broken tablets and the percentage of tablet mass lost through chipping. This testing helps ensure that the tablets can withstand the rigors of transportation without breaking.

So, in summary, friability is a property of materials that easily break into smaller pieces when rubbed or under pressure. It can apply to substances that can become airborne and pose a health hazard, softer rocks that crumble easily, tumors that are easily torn apart, and tablets that need to withstand transportation.