10 responses

  1. kitty Tonny
    January 13, 2011

    What Makes Glass?

    Glass is made using three different minerals:
    1.Sand (silica)
    Intense heat changes sand into a fragile form of glass.
    2.Soda ash (sodium carbonate)
    This is a powdery white material that is added to the mixture to lower the melting temperature of the sand.
    3.Limestone (calcium carbonate)
    This is added to make the glass stronger.
    The raw materials are melted together in a furnace at a temperature of 1600 C. This is the same temperature as a jet engine!

    What Makes Crystal?

    The inclusion of at least 24% lead oxide in the composition is required by law for crystal to be called full lead crystal. The lead lends brilliance and weight to the product. Crystal without lead is still crystal, i.e. clear glass, however, it is more commonly perceived as “glass”. The lead also make the crystal softer and more conducive to cutting. This is why the lead crystal is cut and for the most part, the unleaded crystal is not cut.

    Difference Between Crystal and Glass

    Defining the difference between crystal and glass is not an exact process. While is it true that all crystal is also glass, only certain types of glass can be properly identified as crystal. But within some countries, the qualities that must be present in order for glass to earn the title of crystal may vary.

    The lead content of glass is usually a determinant in the classification of finished goods as either crystal or glass.

    In the European community, glass items that have more than four percent but less than ten percent of lead monoxide usually earn the designation of glass. While this is not always the case, glass that is found to have a lead content of eight to ten percent is granted the status of lead glass. Glass goods with a lead monoxide content of between ten percent and thirty percent earn the designation of crystal. In the event that the lead monoxide content exceeds thirty percent, the item is often identified as lead crystal.

    In the United States, a lead monoxide content of one percent is sufficient for glass to be classified as crystal. In other countries around the world that do not adhere strictly to the standards used by the European community, the range of lead content required before glass can be identified as crystal may range from anywhere between three percent to fifteen percent. Glass with a higher lead monoxide content would be classified as lead crystal.

    Advantages of Crystal

    Crystal has higher lead content. This give crystal a high index of refraction which makes it sparkle when cut at sharp angles and gives the glass a distinctive long lasting ringing tone when it is struck gently with a hard object like a fingernail. The lead may leach out into acidic beverages. The glass is also more fragile and subject to temperature shock.

    More: http://www.etchedcrystals.com/knowledge/Crystal-versus-Glass.html


  2. Eric
    October 14, 2016

    Just discovered your site and I love it!I wanted to reach out to you and see if you would be willing to test out some of my glass etching craft supplies for free for feedback. Any interest? Shipping of the supplies will be free as well. Looking forward to hearing your thoughts. Thanks Eric


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