How to Distinguish Leaded Glass from Normal Glass How to Distinguish Leaded Glass from Normal Glass
Leaded glass, commonly known as crystal, can look and feel similar to regular glass, if you do not know what to look for. Many people don't even realize there is that much of a difference. Leaded glass is made up of the same basic components as manufactured glass, with the addition of one important ingredient: lead oxide. This chemical is used by glassmakers during firing as a quality enhancement. Leaded glass is used for more detailed glassware, and can usually be distinguished from ordinary glass based on physical properties like cut and clarity. To properly determine whether an product is made from leaded crystal or regular glass, you will need to examine these areas in a crystal object and weigh them against ordinary glassware.
Step 1 - Judge Clarity
Due to a higher lead content, crystal has a high optical clarity, often appearing clear or even white in color, hence the term "crystal clear". Glass cannot achieve the same level of purity, therefore the object will often have a yellowish/greenish cast or tint instead.
Step 2 - Compare Cuts
The addition of lead to glass not only enhances clarity, it softens the glass, making it easier to cut. Unleaded glass cuts will be rougher and obvious to the touch, whereas with crystal the cuts have a more refined texture and precise look.
Step 4 - Compare Weight
The addition of lead to a glass object will increase it's molecular density, causing crystal to be noticeably heavier than glass. Hold your glass object in one hand and the crystal object in another, the crystal will be weightier and more dense than the glass object by comparison.
Step 5 - Tap the Brim
When struck, crystal will transmit a clear ringing sound or "ding". Tap your crystal object and test its sound clarity. The clearer the ring, the higher the lead content. Tap your glass object and you will notice the glass only makes a dull thumping sound. This is because crystal is bonded together more closely due to the lead content and therefore absorbs less energy than ordinary glassware.
Step 6 - Hold It to the Light
The simplest way to tell the difference between glass and leaded crystal is to hold each object up to a light source. Crystal is well known for its high spectacular refraction and its inherent ability to bend light. If you hold an object up to the light and it sparkles and throws the light into a dazzling pattern, this object is made of leaded crystal, not regular glass.