Jewellery marked with a 950 stamp indicates the precious metal has a 95% purity. This number relates to both Platinum and Palladium. However, PT 950 or PLT 950 identifies Platinum.
The number 950 denotes 950 parts per 1000 parts within the item. In the UK, this purity (or fineness) includes a hallmark once verified by one of several Assay Offices. Hallmarks can be stamped or laser-etched onto jewellery by each Assay Office.
950 Stamp and no Hallmark
Most items above 1 gram in weight in the UK, should feature a hallmark. This legal requirement ensures buyer confidence and reassurance when purchasing items of jewellery. Otherwise, how do you know an item carries the purity suggested by the stamp?
PT – Periodic Table Elements
The stamp PT represents Platinum as shown on the Periodic Table of Elements. Shown alongside 950 the stamp simply identified 95% pure Platinum metal. PLT simply abbreviated the word rather than to use the reference from the Periodic Table.
Trust issues with 950 the stamp vs a hallmark
The problem with stamps derives from the possibility that any item of metal could be inscribed, laser-etched, or stamped with a mere word, number, or symbol. By comparison, an official 950 Platinum hallmark guarantees the fineness (purity) of your purchase. However, many antique pieces of jewellery feature stamps. Often, hallmarks wear from jewellery or become accidentally removed due to work such as resizing items. However, even antique items of Platinum jewellery can be tested to verify their authenticity. But, this is often unnecessary when purchasing from an antique jewellery specialist or at least from a reputable jeweller.
Additional help with jewellery stamps
Over the years, we have featured several articles in our blog on precious metal stamps. For example, our popular post on 916 gold stamp became one of our most read articles. Some of our other posts even include help on issues faced with some precious metals. For example, Platinum rashes and even upgrading from Gold to Platinum and the pros and cons of this choice.
About Mark Johnson
My name is Mark and I'm founder at Serendipity Diamonds. I have 30 years or experience in polished diamonds and jewellery. Today, I work with an expert team in our Isle of Wight jewellery showroom located in Ryde. Most of my work involves helping clients in our showroom, working on our two websites and photographing jewellery commissions.
