Have you ever wondered what your fancy wine glasses are made of and why they are called crystals? What about that expensive miniature crystal swan you have in your cabinet?
The word “crystal” is a loosely used word which can refer to a myriad of things. Needless to say, it creates confusion and a lot people associate the word to mean natural quartz. This is just not so. Crystal can mean, among others, both glass and quartz. Other natural stones are also often included in the meaning of crystal. When the word crystal is used to refer to glass, it is of the lead glass type, meaning the glass is heated longer at lower temperature. For the purpose of this blog, I do not differentiate between lead glass (which can be called crystal) and glass (which cannot be called crystal). I will refer to both as glass.
The type of Quartz most often confused with glass is the clear quartz variety, where it can appear transparent and colourless. The common quartz contains plenty of inclusions, fine bubbles, and tones of cloudiness and is easily distinguishable from glass. Rock Crystal, however, is a type of clear quartz which is totally transparent and colourless and appears as clear as glass and is in general more expensive than the common variety of clear quartz.
So how do you tell the difference between rock crystal and glass? Quartz is harder than glass and, like diamonds, will scratch and cut glass easily, but it is often not practical to whip out a piece of glass from your pocket, or the piece of quartz you are trying to test may not have a sharp edge, or you may not even be allowed to use the quartz for testing before you buy it in the first place.
First thing first, wine glasses, table bowls, and all tableware are very likely to be glass, the so-called crystalware. They are made with lead glass, there is no quartz in them. The same goes with crystal decorations and jewellery from expensive leading brands. These products are manufactured with lead glass, some of them claim to have some “quartz dust” in them. Some of them may even have natural quartz, but then they would say so. The rule of thumb is, if the seller only vaguely claims that it is crystal then it is likely to be just crystalware, i.e. glass.
Your biggest problem is when buying items such as crystal balls or pendulums or other items which the seller claims to be of a specific stone. The easiest way to test it is by tapping the stone lightly with your nail. Glass will give sharp pings, quartz does not. Even though quartz is harder than glass, the surface of glass has the hard finality feel to it whereas quartz has a softer feel. Glass also feels colder, especially on cold days. You can differentiate the common varieties of quartz from glass visually with ease; if the item is absolutely homogenous and perfect, it’s glass; but it is a lot harder to differentiate glass from rock crystal. This is where experience comes in but most people do not have this luxury. You can, however, look at the seller – do they sell similar items, do other items look fake or real, etc. Another thing I always look for is if the item comes in a very elaborate silk or velvet lined box/container. I will get suspicious right away. Remember that rock crystal is expensive, you can’t get a sphere with stand and silk lined box for $20 postage inclusive.
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