Skip to content

Tag Archives: GIA

Imitation Gemstones– Buyer Beware

A client brought these three stones to our shop looking to sell them. She had purchased the stones while traveling and was under the impression the two 30 ct. greenish blue ones were aquamarines and the peachy pink stone was morganite. At Mardon, as gemologists, we always buy gems very carefully and only when we […]

Padparadschas R Us – Rare Gems Are Our Specialty

We’ve always loved the ultra rare variety of fancy sapphire known as the Padparadscha. Early in my career, working in the gem indentification labs of GIA, I had the opportunity to see a few good examples of the natural Padparadscha Sapphire and to learn the subtle distinctions that make this gem so desirable. Our informational blogs about this […]

Topaz or Not Topaz? That is the Question!

One of the missions Robert M. Shipley defined when he created the Gemological Institute of America was to rectify incorrect practices in the jewelry and gem business. One of the most common of these is the use of trade names and misnomers for gemstones. Before the development of the gemological sciences, it was common for gem […]

Repairing Broken Hearts and Broken Diamonds

    Our client sadly thought this family heirloom .96 ct. Old European cut diamond had little or no value– after years of wear, it had been cherished almost to death and looked like it had been through the garbage disposal. Mardon to the rescue! A close inspection in our gemological microscope revealed that while […]

Who can call himself a jewelry appraiser?

This headline caught my eye in a recent email— the answer to this trick question is anyone! A newsletter by an insurance industry organization highlighted the fact that there are no federal or other governmental bodies setting qualifications for who may be a jeweler or a jewelry appraiser. A study by a related group also […]

Appraising Fancy Color Diamonds

We just appraised this beautiful bright yellow ~2 ct. round diamond for a client. She had inherited the stone, which was accompanied by an appraisal from a gemologist which described it as a “Canary Yellow” diamond, which implied but didn’t state specifically that the stone was natural-color. Our client said the diamond had originally been […]

What is a Built-up Diamond?

These days, we buy a lot of jewelry, used as well as new. Last week, I worked with a young lady, a bit down on her luck and on the rebound from a relationship that didn’t work out. She was looking to sell her white gold solitaire ring that was set with the one carat […]

The Perils of Paraiba– Jewelers Tears #2

This tale of woe illustrates some of the risks and challenges we jewelers face in our fascinating business. Last year, I had seen this lovely 8.65 ct reddish purple cuprian elbaite tourmaline several times. Gem dealer Jack had tried mightily to tempt me with it, an unheated stone from the country of Mozambique in East […]

The Rarified World of the Rarest of Gems

Our old friend and former colleague at GIA, Gary Roskin, has published an absolutely fascinating account of a major event at the pinnacle of the gem world. Under the auspices of the Smithsonian Institute, the most famous of all gems, the Hope Diamond, was brought together for the first time with the Wittelsbach Blue, now […]

Restoring the Ring of GIA founder Robert M. Shipley- A Father’s Legacy

We thought this would be a great post the week after Father’s Day. Often at Mardon Jewelers, we’re asked to perform an expert service by a client. Such was the case recently when we restored the ring that originally belonged to Robert M. Shipley, the founder of GIA. Early in his career, Mr. Shipley realized […]