Diamond Times

One of the largest blue diamonds ever found ‒ weighing in at 122.53 carats (cts.) ‒ was unveiled this week by Petra Diamonds, owner of the historic Cullinan Mine in South Africa, a 111-year-old mine that has produced some of the most famous diamonds in history. Petra said the stone would be sold after it has “analyzed the diamond to assess its potential value…and… its optimal route to market.” The Cullinan, opened in 1903, produced the largest diamond ever found, the 3,106 ct. Cullinan diamond, which was cut into the 550 ct. Cullinan I that remains the centerpiece of the...

Birthstones & AnniversariesRuby is the birthstone for July and the gem for the 15th and 40th anniversaries. Rubies can command the highest per-carat price of any colored stone. This makes ruby one of the most important gems in the colored stone market. In its purest form, the mineral corundum is colorless. Trace elements that become part of the mineral’s crystal structure cause variations in its color. Chromium is the trace element that causes ruby’s red color.Ruby is the most valuable variety of the corundum mineral species, which also includes sapphire. Rubies can command the highest per-carat price of any colored stone....

Emerald is the green to greenish blue variety of beryl, a mineral species that also includes aquamarine as well as beryls in other colors. Gem experts differ on the degree of green that makes one stone an emerald and another stone a less-expensive green beryl. Some people in the trade tend to give the name emerald to any green beryl colored by chromium. But to most gemologists, gemological laboratories, and colored stone dealers, it is more correct to call a stone green beryl when its color is "too light" for it to be classified as emerald. Even among that group,...

Diamonds in the normal color range are colorless through light yellow and are described using the industry’s D-to-Z color-grading scale. Fancy color diamonds, on the other hand, are yellow and brown diamonds that exhibit color beyond the Z range, or diamonds that exhibit any other color face-up. These rare specimens come in every color of the spectrum, including, most importantly, blue, green, pink, and red. Gem diamonds in the D-to-Z range usually decrease in value as the color becomes more obvious. Just the opposite happens with fancy color diamonds: Their value generally increases with the strength and purity of the...

The name “aquamarine” is derived from two Latin words: aqua, meaning “water,” and marina, meaning “of the sea.”  It has been said that the mineral beryl gives the wearer protection against foes in battle or litigation. It makes the wearer unconquerable and amiable, and also quickens the intellect. Aquamarine is the birthstone for March. Aquamarine is the green-blue to blue variety of the mineral beryl. (Emerald is the green to bluish green variety of the same mineral.) Its color is usually a light pastel greenish blue.  Heat treatment usually gives it a more bluish appearance. Aquamarine crystals are known to...