Antique Seal Collection: Carnelian and Hardstone Intaglios

• Carnelian Glass - Carnelian glass is a type of glass that is colored red, orange, or brownish-red. It is made by adding iron oxide to the glass mixture. The color of carnelian glass can vary depending on the amount of iron oxide that is added, as well as the firing temperature. Carnelian glass is often used to make beads, jewellery, and other decorative items. It can also be used to make stained glass windows and other art objects. Carnelian glass is sometimes called "carnelian chalcedony" or "carnelian quartz."
  
  Carnelian glass was first made in the Roman Empire. It was also made in ancient Egypt, Greece, and Mesopotamia. Carnelian glass was not made again until the Renaissance, when it became popular again. Today, carnelian glass is made in many countries around the world.
• Hardstone - Hardstone is not a scientific name for a particular gemstone, but a word used to describe any one or more semi-precious stones used in jewellery and decorative arts, and can include jade, agate, onyx, rock crystal, amber, jet and carnelian. Softer stones and minerals such as soapstone, and alabaster and hard stones used in building such as marble or granite are generally excluded.
• Intaglio - A term used to define a method of decoration most common in glassmaking and jewellery which involves engraving, carving or moulding an image into the background, leaving an impression, and leaving the top surface of the item flat, the opposite to relief carving, and also know as counter-relief.

This item has been included into following indexes:

• seals, for documents - European 450