As an antiques appraiser, Dr. Laurie has encountered many people who struggle to differentiate between valuable glass and inexpensive, mass-produced glass. Glass can be tricky because it is relatively inexpensive to manufacture, which means that there is a lot of it out there. This can make it difficult to determine what is valuable and what is not.
One of the most important distinctions to make is between pressed glass and cut glass. Most of us have a piece of what’s called soda-lime glass in our homes, which is a relatively cheap and junky type of glass that is commonly used for things like drinking glasses. Pressed glass and molded glass are similar types of inexpensive glass.
Cut glass, on the other hand, is a more valuable type of glass that has been cut to create intricate patterns and designs. To determine whether a piece of glass is cut, simply run your thumb over the decoration. If it’s smooth, the glass is likely pressed or molded glass. If it feels sharp and you feel like you might get cut, then you have a piece of cut glass.
One type of cut glass that is particularly coveted by collectors is cobalt blue glass. This glass has a deep, rich blue color that is achieved through the addition of cobalt oxide to the glass mixture. Cobalt blue glass was popular in the late 19th and early 20th centuries, and was used for a variety of decorative objects such as vases, bottles, and serving dishes.
If you are unsure about whether a piece of glass is valuable or not, Dr. Laurie recommends taking a photograph and consulting with an antiques appraiser. Alternatively, you can attend one of her appraisal events, where she can evaluate your glass in person.
In summary, identifying valuable glass requires an understanding of the differences between cut, pressed, and molded glass. By running your thumb over the decoration, you can determine whether a piece of glass is cut or not. If you are a collector, keep an eye out for cobalt blue glass, which is highly sought after by collectors.