Everything that does not fall into the Precious Gemstones category was seen as semi-precious gemstones, or a semi-precious stone. Think of quartz, grenade, pearl and much more. The name of semi -precious stone is actually no longer of this time and does wrong with these precious stones. Some semi -precious stones can now also be worth much more than the "big four" precious stones. Now you definitely wonder how that is possible. That is because of how a gem scores on a number of factors. When determining the value of a gemstone, the following factors are considered:

• Colour
• Purity
• Shark
• Carat weight
• Rarity
• Origin
• Sustainability
• Optical properties
• Half -pace

We have further explained the first four factors for you. 

Precious stones are often formed under a huge natural disasters which can cause small inclusions in the precious stones. Including can best be seen under a microscope or a loop. The number of inclusions and the place determines the purity of a gem. The higher the purity of gemstone, the higher the value. The Gemmological Institute of America (GIA) has subdivided colored gems into purity:

• Very clearly visible inclusions
• clearly visible inclusions
• Visible inclusions
• Hardly any visible inclusions
• clean before the eye

In addition, there are gemstone species that contain more inclusions than others. This is also taken into account when determining the value. The GIA has categorized a number of gems based on how probably the gems contain inclusions:

Type I: precious stones that usually do not contain any inclusions that are visible to eye. Aquamarine is one of them.

Type II: gems that contain some inclusions that are visible to the naked eye. For example Robijn.

Type III: gems that usually contain many inclusions that are visible to the naked eye. Think of emerald.