Power of Gemmology By Prachur Singhal

Gold is the only metal that is yellow or "golden". Other metals may develop a yellowish color, but only after they have oxidized or reacted with other chemicals. Nearly all of the gold on Earth came from meteorites that bombarded the planet over 200 million years after it formed. The element symbol for gold is Au. The symbol comes from the old Latin name for gold,  aurum , which means "shining dawn" or "glow of sunrise". The word "gold" comes from the Germanic languages, originating from the Proto-Germanic  gulþ  and Proto-Indo-European  ghel , meaning "yellow/green". The pure element has been known since ancient times. Gold is extremely ductile. A single ounce of gold (about 28 grams) can be stretched into a gold thread 5 miles (8 kilometers) long. Gold threads can even be used as embroidery thread. Malleability is a measure of how easily a material can be hammered into thin sheets. Gold is the most malleable element. A single o...

In the spring of 2017, the Gübelin Gem Lab received a yellow pearl necklace for testing. The size and color of the specimens implied that they were South Sea cultured pearls. The high insurance value appeared to confirm this; however, there were some suspicious color patches that suggested the material had been dyed. Only a few months earlier, author LK visited the Hong Kong office of Grace Pearls, a large producer with a pearl farm and factory in China, to see their latest batch of freshwater cultured pearls. Grace Pearls developed a proprietary method to grow large freshwater pearls with bead, marketed as “Edison” pearls. These occur in all the known colors of traditional freshwater pearls, typically white, orange, pink, and purple. To  complement their color range, they also offer yellow and black treated pearls ranging from approximately 12 to 18 mm. The goods we saw at Grace Pearls had a wide range of qualities and prices. The lowest price for a strand of Edison pe...