A question that is often asked is what are gemstones, can all minerals be gemstones? The short answer to the second part is: No, some minerals will never be a gemstone.
The longer answer is: it depends on how you define “gemstone”.
What Are Gemstones’
The most common way to define gemstones is simple: if it’s cut or polished and is used in jewelry it’s a gemstone. If you define a gemstone in this way there are a lot of minerals that qualify.
For example the well-known diamonds and rubies. However other materials that can hardly be called a mineral qualify as well.
Materials that are not minerals but organic matter, pearls and amber for example. Some rocks can be qualified as gemstones as well, lapis lazuli is often made up of dozens of minerals.
If you take the common definition, then yes, all gemstones can be minerals. You just have to cut or polish them and then set it in a piece of jewelry. In practice however this will never happen.
Certain minerals are either far too small to ever be used, like certain platinum group crystals. Others are far too fragile to polish, let alone cut, an example of this would be zeolite.
There also are minerals that nobody in their right mind would want to wear. The most obvious example being white and blue asbestos, which can cause lung diseases including lung cancer.
The main reason why some minerals will never be gemstones is simply because they are far too common or are just not beautiful enough.
So while it certainly is possible for all minerals to be gemstones if you take the common definition. In practice only a very small amount of minerals will ever be gemstones, a title they will have to share with certain rocks and organic matter.