By Teresa Frye, TechForm Advanced Casting
While diamonds and colored gemstones take the main stage in the vast majority of fine jewelry, the precious metals that are used to mount these objects of beauty have their own captivating story as well. More than mere carriers of precious stones, the elements that we rely upon to remain beautiful and perform over decades of routine wear are inherently of special quality. In my next few posts I will reflect on the unique physical attributes of platinum and gold, the dominant metals used in the making of fine jewelry.
Platinum is the king of metals. Aside from its extreme rarity, I find it fascinating that platinum’s particular physical qualities are unmatched by any other element in nature. Its characteristics are so special that it is difficult to find lower cost substitutes in many of the applications where it is used. And at over $1,000 per ounce, believe me, people try all the time.
Platinum is very inert, meaning in the jewelry world that it will not corrode, tarnish, nor spur allergic reactions in humans. This is very rare in metals, with fine gold being the only other element that even comes close. Platinum also rates very high on the toughness scale, which is a scientific measure of a material’s ability to absorb energy when impacted without breaking. It is also very malleable, easy to form, and has no spring-back (or memory as it is called in tech speak). Once set in place, a platinum prong will hug your stone tightly and for life in a way no other metal can.
Platinum is incredibly dense. It is the third densest element on earth and is only exceeded by osmium and iridium, two other platinum group metals. As such it is highly prized for its radiopacity (inhibits the passage of electromagnetic radiation). Often used in implantable devices and visible surgical guides inside the human body, nothing else displays quite so clearly and crisply under x-ray as platinum. Platinum is also a key ingredient in chemotherapies to fight cancer, so it is actually saving lives every day.
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| The 24.18-carat "Cullinan Dream" diamond set to go on auction June 9 is set in a platinum ring flanked with classic baguette-cut diamonds. |
Another powerful feature of platinum is that it remains very stable under extreme temperatures. Many of the world’s high temperature thermocouples are made of a combination of platinum and rhodium. As a caster, I am well-versed in the extreme temperature resistance of platinum. There is no other metal routinely cast that melts at such high temperatures, and this is one reason platinum is among the most difficult metals to cast. This high temperature resistance further translates into industrial uses such as jet engine and glass making components, where the use of anything else might result in corrosion or melting.
As a key material used in many catalytic converters for auto emissions, platinum plays a strong role in cleaning the world’s air. Platinum’s unique ability as an auto catalyst is partially substituted with palladium, another platinum group metal, but for many applications platinum remains a needed catalyst. While there are many other industrial and medical uses, hopefully this sampling demonstrates a few of the reasons why this element is so unique and prized for its performance attributes.
Today’s bridal consumer is very inquisitive about the materials they are purchasing. Survey after survey has confirmed this fact, and thus a good knowledge of platinum and gold as elements on the periodic table can go far not only to educate the consumer about their metal choice, but also to set yourself apart as expert in every aspect of what you sell.
Platinum in summary:
* The third densest element on earth, only exceeded by osmium and iridium.
* A very inert metal, meaning it is highly resistant to chemical corrosion, even at high temperatures. Platinum jewelry alloys simply do not tarnish.
Hypoallergenic, meaning platinum is very unlikely to cause an allergic skin reaction in humans.
* Extremely tough - platinum will resist breakage to a much greater extent than metals that are much harder and typically more brittle.
* Extremely durable - platinum jewelry will not corrode and wear thin over time, as will most karat gold alloys.
* Extremely high melt temperature - platinum alloys have the highest melting temperatures of any metals that are routinely cast, and this includes industrial metals.
* Human and environmental uses - platinum is widely used in applications that save lives and improve air quality. Cancer fighting drugs utilize platinum as a key ingredient and platinum’s strength as a catalyst helps clean auto emissions worldwide.
* Extremely rare investment in a piece of platinum jewelry brings more than the joy of owning a spectacularly beautiful heirloom piece. It can also be seen as an investment in a rare and precious element with high intrinsic value in its own right.
Teresa Frye is founder of TechForm, which specializes in the casting of platinum group metals for the jewelry, medical, and aerospace industries. She is also founder of the Portland Jewelry Symposium, an annual gathering of custom jewelers, designers, and retailers described as a “great think tank” for jewelers who are passionate about their craft. Frye is a renowned specialist on the casting of platinum group metals who speaks at jewelry events throughout the world.
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