ArtsAutosBooksBusinessEducationEntertainmentFamilyFashionFoodGamesGenderHealthHolidaysHomeHubPagesPersonal FinancePetsPoliticsReligionSportsTechnologyTravel

Different Kinds Of Glasses, And How They Are Made

Updated on September 24, 2011

Glass has been used since very early times; the Egyptians used glass nearly four thousand years ago. Chinese learned to manufacture glass comparably later than the Mesopotamians and Egyptians. The first Chinese glasses are dragon-eyed beads produced during the Warring State period (5th century BC), . American Indian didn’t know glasses at all before Columbus. When Columbus and his sailors came ashore, carrying swords, speaking oddly, the Arawaks ran to greet them, brought them food, water, gifts. Columbus exchanged glass beads for food, water and gold. He later wrote of this in his log:

They brought us parrots and balls of cotton and spears and many other things, which they exchanged for the glass beads and hawks' bells.

The basic materials used for making glass are the same as those used centuries ago - sand, soda and lime. The simplest type of glass is made by heating calcium carbonate, sodium carbonate and sand (silica) until the mixture melts to give a transparent liquid. On cooling, this solidifies to give glass.

Glass is not a single substance but an amorphous, homogeneous mixture. It does not melt at a definite temperature and is not really a solid. It is said to be a supercooled liquid.

Kinds of glass

The major disadvantage of ordinary glasses is that they are brittle and crack when subjected to sudden changes of temperature. During manufacture, the ingredients used for making glass are changed suitably to obtain specific properties. Some common types of glass are described below.

Soda glass: This is a mixture of sodium and calcium silicates used for making bottles, beads, marbles, etc.

Potash glass: This is a mixture of potassium and calcium silicates, also known as hard glass. Potassium carbonate is used instead of sodium carbonate for making this glass. It can resist high temperature without melting.

Pyrex glass or borosilicate glass: This contains a mixture of borosilicate of calcium and aluminium. It is made from sand, sodium carbonate, alumina and borax. This glass can withstand sudden changes of temperature without cracking. Therefore it is used for special laboratory glassware and for ovenware.

Cut glass or optical glass: This contains some lead oxide along with potassium and silica. This kind of glass, also called lead crystal glass has a high refractive index. It is used for making lenses, prisms, high quality art objects and expensive glassware. Cut glass shows a high degree of brilliance and sparkle.

Crookes’ glass contains some rare earth elements and is used for special optical lenses.

Shatterproof glass or laminated glass: This is made of several sheets of glass cemented together with some transparent adhesive. Bulletproof glass consists of several alternate layers of plastic and glass. Laminated glass is used in aeroplanes, windshields of cars and bulletproof screens.

Fibre glass: if a glass rod is heated in the middle and pulled apart as it softens, it can be drawn into thin fibres. Glass wool is a bundle of loose glass fibres. It is an excellent heat insulator and is therefore used as insulating material in refrigerators, ovens, cookers and hot water bottles.

Glass fibres are light yet strong, weather proof, fire proof, corrosion free and poor conductors of electricity. They are used for sound proofing and insulation of buildings. Layers of glass fibres when bonded with adhesives produce fibre glass. This can be moulded into any shape and is used in motor car bodies, boats and aeroplane wings.

Coloured glass: Glass can be coloured by the addition of certain metals or metal salts to the silicate mixture during fusion.


The necessary raw materials (sodium carbonate, calcium carbonate and silica for ordinary glass) are taken and ground to a powder. Broken bits of glass are also added. This is called “cullet”. The addition of cullet lowers the melting point. This mixture called “batch” is heated to about 1400oC when it melts.

When all gases like carbon dioxide and air escape, the necessary colouring materials are added. Heating is continued until it melts. This worked to get the required articles. It can be blown into the desired shape using a long pipe or moulded into articles and cooled.

If the finished articles is suddenly cooled, it would become very brittle. Instead it is gradually cooled, and the process is called “annealing”. the articles to be annealed are kept on a slowly-moving belt passing through a narrow chamber called “lehr”. One end of the chamber is hot and the temperature gradually decreases until it is room temperature at the other end. It takes several days for the articles to reach form one end to the other end and so they are cooled very slowly.


    0 of 8192 characters used
    Post Comment
    • katrinasui profile image


      7 years ago

      Very informative hub. I learned something new today.


    This website uses cookies

    As a user in the EEA, your approval is needed on a few things. To provide a better website experience, uses cookies (and other similar technologies) and may collect, process, and share personal data. Please choose which areas of our service you consent to our doing so.

    For more information on managing or withdrawing consents and how we handle data, visit our Privacy Policy at:

    Show Details
    HubPages Device IDThis is used to identify particular browsers or devices when the access the service, and is used for security reasons.
    LoginThis is necessary to sign in to the HubPages Service.
    Google RecaptchaThis is used to prevent bots and spam. (Privacy Policy)
    AkismetThis is used to detect comment spam. (Privacy Policy)
    HubPages Google AnalyticsThis is used to provide data on traffic to our website, all personally identifyable data is anonymized. (Privacy Policy)
    HubPages Traffic PixelThis is used to collect data on traffic to articles and other pages on our site. Unless you are signed in to a HubPages account, all personally identifiable information is anonymized.
    Amazon Web ServicesThis is a cloud services platform that we used to host our service. (Privacy Policy)
    CloudflareThis is a cloud CDN service that we use to efficiently deliver files required for our service to operate such as javascript, cascading style sheets, images, and videos. (Privacy Policy)
    Google Hosted LibrariesJavascript software libraries such as jQuery are loaded at endpoints on the or domains, for performance and efficiency reasons. (Privacy Policy)
    Google Custom SearchThis is feature allows you to search the site. (Privacy Policy)
    Google MapsSome articles have Google Maps embedded in them. (Privacy Policy)
    Google ChartsThis is used to display charts and graphs on articles and the author center. (Privacy Policy)
    Google AdSense Host APIThis service allows you to sign up for or associate a Google AdSense account with HubPages, so that you can earn money from ads on your articles. No data is shared unless you engage with this feature. (Privacy Policy)
    Google YouTubeSome articles have YouTube videos embedded in them. (Privacy Policy)
    VimeoSome articles have Vimeo videos embedded in them. (Privacy Policy)
    PaypalThis is used for a registered author who enrolls in the HubPages Earnings program and requests to be paid via PayPal. No data is shared with Paypal unless you engage with this feature. (Privacy Policy)
    Facebook LoginYou can use this to streamline signing up for, or signing in to your Hubpages account. No data is shared with Facebook unless you engage with this feature. (Privacy Policy)
    MavenThis supports the Maven widget and search functionality. (Privacy Policy)
    Google AdSenseThis is an ad network. (Privacy Policy)
    Google DoubleClickGoogle provides ad serving technology and runs an ad network. (Privacy Policy)
    Index ExchangeThis is an ad network. (Privacy Policy)
    SovrnThis is an ad network. (Privacy Policy)
    Facebook AdsThis is an ad network. (Privacy Policy)
    Amazon Unified Ad MarketplaceThis is an ad network. (Privacy Policy)
    AppNexusThis is an ad network. (Privacy Policy)
    OpenxThis is an ad network. (Privacy Policy)
    Rubicon ProjectThis is an ad network. (Privacy Policy)
    TripleLiftThis is an ad network. (Privacy Policy)
    Say MediaWe partner with Say Media to deliver ad campaigns on our sites. (Privacy Policy)
    Remarketing PixelsWe may use remarketing pixels from advertising networks such as Google AdWords, Bing Ads, and Facebook in order to advertise the HubPages Service to people that have visited our sites.
    Conversion Tracking PixelsWe may use conversion tracking pixels from advertising networks such as Google AdWords, Bing Ads, and Facebook in order to identify when an advertisement has successfully resulted in the desired action, such as signing up for the HubPages Service or publishing an article on the HubPages Service.
    Author Google AnalyticsThis is used to provide traffic data and reports to the authors of articles on the HubPages Service. (Privacy Policy)
    ComscoreComScore is a media measurement and analytics company providing marketing data and analytics to enterprises, media and advertising agencies, and publishers. Non-consent will result in ComScore only processing obfuscated personal data. (Privacy Policy)
    Amazon Tracking PixelSome articles display amazon products as part of the Amazon Affiliate program, this pixel provides traffic statistics for those products (Privacy Policy)