All posts filed under: Gem Highlight of the Week

Gem Highlight of the Week: Moonstone

For this week’s gemstone highlight, I thought we could continue along the mystical moon vein started last week by taking a look at the moonstone. All hallows’ eve is coming up soon, after all. Geology | Origins of a Gemstone Moonstone originates from the “potassium aluminosilicate” variety of the large mineral group of feldspars. With feldspar making up over half of the Earth’s crust composition, it’s likely that you could pick up a rock anywhere in the world, and it would probably contain at least one mineral from the feldspar group (University of Minnesota, Potassium Feldspar). In its rough form, potassium feldspars typically form pink, reddish or white, hard blocky crystal masses. The potassium feldspar series has its own sub-varieties, including: orthoclase, sanidine, oglioclase and microcline. Moonstone is typically cut from the sanidine or orthoclase. Sanidine is a high temperature form of potassium feldspar and has a less ordered crystal structure than orthoclase. It is primarily found in volcanic igneous rocks where magmas cooled more rapidly and crystals have less time to form, resulting in …

Gem Highlight of the Week: Blue Moon Diamond

Autumn is officially upon us. Yippee! The foliage is a burst with color and the proliferation of pumpkins and ghostly paraphernalia throughout the neighborhood point to a Halloween spirit in full swing. Did anybody have the opportunity to observe late September’s supermoon? With the moon in mind, I wanted to feature the Blue Moon Diamond as our gem highlight of the week. As you may have heard last month, it is poised to sell for as much as $35 to $55 million when it goes to auction at Sotheby’s in Geneva mid-November (Mosendz, “Big Blue Moon Diamond…”). Aptly titled after the phrase “once in a blue moon,” this rare, 12.03 carat, fancy vivid blue diamond has been deemed internally flawless in clarity by the Gemological Institute of America (GIA). What truly distinguishes this gem is its exceptionally unique color. In comparison to the colorless varieties that most consumers are familiar with– if for no other reason than the classic diamond engagement ring–, fancy colored diamonds are a rarity, and therefore much more valuable. The Blue …