How to determine the condition of glass like an expert

This article will explain common glass condition issues.  It will help you determine if these condition issues are present in your glass object. 

Always handle glass with clean, dry hands and remove rings or dangling bracelets.  Never place pressure on small parts or applied decorative handles when picking up these objects. Remove any detachable components, such as a lid, before handling the object. Never drag a glass piece across a surface because this can scratch the object. When examining the bottom of a glass object, lay down a thick towel or folded cloth on the table to protect it from damage.

Keep in mind that if you discover condition issues, they will not necessarily hurt the sales value of your item. Experts can determine whether restoration will increase the potential resale value of your item.

Once you’ve set up the glass object for examination, you should look for the following issues:

• Chips or Flea Bites
• Cracks and Stress Lines
• Cloudiness or “Sickness”
• Scratches

• Chips or Flea Bites
  Carefully run your fingers around the rim, base and body of the piece. Do you feel any sharp spots or see any visible losses? Tiny nicks, called “flea bites,” are small losses that are too small to reasonably measure and can be detected using either a magnifying glass or your fingers. You can see chips and flea bites on the base of this bottle in the photograph below.
  
• Cracks and Stress Lines
  Cracks can be caused by impact or exposure to extreme hot or cold temperatures. These are larger and more critical than stress lines, which often appear around handles and other areas where the glass has been frequently touched, and areas where glass parts have been bolted together. Unlike cracks, stress lines are short, fine lines that do not seriously compromise the structural integrity of the piece.  
• Cloudiness or “Sickness”
  If the glass is no longer transparent in certain areas, and you’ve recently washed and dried the object to remove any surface soiling, it may be what experts and collectors call “sick.”  Glass sickness is frequently seen in decanters that were exposed to water with a high mineral content, and in salt shakers that were used for a long period of time.  
• Scratches
  Scratches are usually found on the underside of an object, but can also occur in other areas, such as handles or interiors.