Window in a  Gemstone

First, how do windows in gemstones appear? 

Windows in gemstones would appear when the pavilion of the gemstone is cut shallowly causing the light to pass through instead of being reflected. 

So a window in a gemstone is the transparent area in the body of the gem. It is the part of the body of the gem that looks watery, or see-through. 

When cutting a gemstone the Cutter will create small mirrors at different angles, he would keep a certain proportion of cuts to reflect light. This in turn would bounce back as a more vivid color once it reaches back to our eyes. 

Now the most common known fact is that a well cut gemstone should have no window.

Most people think that a: 

  • Big window means it’s a horrible gemstone.
  • Medium window is a very bad gemstone.
  • Small window is a bad gemstone.
  • No window is a good gemstone.

As a loose Sapphire trader this standard is true. But when it comes to cutting a gem for a ring, the standard would change. 

  • Big window means it’s a horrible gemstone, -always, True!
  • Medium window is a very bad gemstone, -sometimes bad, sometimes good.
  • Small window is a bad gemstone? NEVER!
  • No window means a good gemstone,-sometimes. 

When cutting a gem, a cutter would have 2 major goals:

1. Make the most beautiful gem out of the raw stone, and

2. To produce the heavier gem from the raw stone. (value by carat weight) 

A gem cutter would also take into consideration 3 dimensions, the Length, Width, and Depth. 

If he cuts the gem too shallow, a window will appear. But if he cuts it proportionately, no window will appear. 

Take note: That a window can make a gem look bigger. The perceived size of a gem does not always correspond to its real carat value. 

For example:

 A 5 carat stone with a window will look bigger than a 5 carat stone with no window. A stone with medium or small window would look bigger than a stone with no window. 

When mounting the stone into the setting, the window on a stone with a medium window would not be obvious, and a small window will not be visible at all.  

The face of the stone will be bigger and the stone will look as good as a stone with no window. 

So how can we say that a stone with no window is always not good?

Depending on the color and the cut of the stone, the face of a gem might end up looking big or small. 

Even if a gem is cut perfectly proportionate, it can still end up making the stone look smaller. 

The cut and windows of the gem can make it either look small or big for it’s real carat value. 

Windows can also enhance the beauty of the gem depending on the depth and vividness of the color of the gem. 

You would find a lot of 5 carat Sapphires that looks like a 3 carat Sapphire. 

When a gem trader buys and sells loose gemstones he will target stones or sapphires without a window. 

A jewelry designer like me would choose a Sapphire with a small window. Because after the gem is placed in the ring, the window won’t appear, but the gem will look bigger. 

So in actuality, what the buyer would see is how big the gem is, which would not correspond to its real carat value. 

A smaller carat gemstone with a window could look like it has a bigger carat because of the window.