Key difference: Glass is the generic name, while crystal is a subspecies of glass - it is made in the same way, but from different materials. Therefore, every crystal is a type of glass, but not every glass can be defined as a crystal. In 1969, the European Union (EU) established three main criteria for categorizing a glass product as "crystal": a lead content of more than 24%, a density of more than 2.90 and a reflection index of 1.545.
From a scientific point of view, crystals are pure substances whose atoms, molecules or ions are grouped in an ordered model, where they extend in all three spatial dimensions. Crystals most often appear naturally on earth. This happens through crystallization and solidification - processes of formation and crystal growth.
The term "crystal" is often used in connection with glassware that has a more elegant shape than everyday glassware. However, this is not the main difference between them. However, the main definition that applies to crystals is "a type of glass that contains lead".
According to John F. Kennedy, head of technical services in Waterford, Ireland, there are very specific guidelines for what a real crystal should contain. There are three main criteria that characterize crystals - lead content over 24%, density over 2.90 and reflection index 1.545. Outside the EU, however, these conditions are not respected. In the United States, for example, any glass with a lead content greater than 1% is categorized as a crystal.
From a technical point of view, the application of the term "crystal" in relation to glass is in itself inaccurate, as glass is an amorphous solid. Therefore, by definition, it lacks a crystal structure, which is necessary for the crystal. Yet the term, although incorrectly applied to glass, has remained and remains popular.
Glassware can be made of different materials - silicon dioxide, zinc, lead, and more recently titanium. Technically, only products with a minimum 24% lead oxide content should be called "lead crystal", while products with a lower lead oxide content or another metal oxide content should be categorized as "crystalline" or "crystalline". glass ". And yet, often all these products fall under the common denominator "crystal".
The color and luster of glass often vary depending on its chemical composition. Glass made with iron oxide has a green tint, while glass made with soda-lime has a bluish tint. Although some people find these shades unattractive, greenish glass is significantly stronger. The crystal is light in color and is mostly transparent. Some pure crystals have the ability to reflect light in different colors. If held in a suitable position, the refraction and dispersion of light from the crystal can create an arc of shades.
Glass is stronger than crystal, so more often crystal products are left for use on special occasions and holidays, while ordinary glass products are used daily. The content of lead in the crystal makes it easier to melt and more accessible and susceptible to fine processing. This allows the products to be made in more detail and to maneuver with the design.
In addition, due to its high lead content, the crystal emits a louder and louder sound with a light tap (toast) than ordinary glassware. Depending on the structure and rarity of the crystal, its price can vary, sometimes drastically.
In conclusion: a crystal is a type of glass made in the same way as glass, but with a different chemical composition. Not every glass is crystalline, but we can safely say that every crystal is a type of glass.
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