In order to be classified as one of the categories of “crystal glass” the material must comply with three different criteria. It must contain oxides of Lead, Barium, Zinc or Potash combined or alone of at least 10%, have a refractive index of above 1.52 and a density above 2.45 grams per cubic centimetre. The Birmingham Assay Office has the specialist resources needed to offer this test, having the expertise and equipment to carry out both chemical and gemmological testing. …

Michael Allchin: Birmingham Assay Office Professor Marylyn Carrigan, Coventry University Centre for Trust and Ethical Behaviour Alan Frampton: Cred Jewellery Gary Wroe: Hockley Mint  

Presentation  Prepared - Check, Venue Prepared - Check, CE & Assay Master Prepared - Double Check!!  2014 is the Hallmarking year of the  date letter "P"  and we are now "P" for PREPARED. Everyone is now off to set up at the Birmingham School of Jewellery, a fitting venue for Michael Allchin's last annual hallmarking review to the jewellery and precious metal trade.