The ring shown to the right, courtesy of Mr. Kanji Hashimoto, was made in the late 19th century. Unfortunately, there is no maker’s hallmark stamped or engraved on this ring, making it impossible to tell who the manufacture is.

The regular use of platinum as a jewelry metal did not start until the early 20th century. This ring is made of yellow gold. Yellow gold generally emphasizes the yellowish color of a diamond; and to avoid this, many pieces of diamond jewelry in the 19th century were made by actually covering the gold with a white metal, usually silver. Many such pieces can be seen in antique jewelry.

Looking at the ring from the back, note the large circular opening behind the diamond. This was done to allow as much light as possible to enter the gemstone from every direction.

Another characteristics of this ring is the manner in which the diamond is cut. This is called an “Old European” cut, characterized by a small table, high crown, and large culet. This diamond’s brilliance has a noticeably different quality than that of a modern round brilliant cut. The main reason for the change in cutting style was the development, around the year 1900, of the ability to saw rough diamond crystals using a thin, flat slat coated with abrasive diamond powder. This technique allows octahedral diamond rough to be polished after first being separated into two pieces. During the era of the Old European cut, diamonds were polished directly from a single octahedral piece of rough, and the crown had to be left high in order to minimize weight loss. This is an example of how technical advances influence the cutting style of high-priced diamonds.