Figure 1. Yellow, brownish gray, and near-colorless anorthoclase feldspar from southeast Vietnam. The rough stones range from 96.5 to 144.8 ct and the cut samples from 3.64 to 11.07 ct. Photos by Le ...

JAS, ‘The Select B2B Show,’ with the continued theme “Connect to Source,” will be held from 5th to 7th July 2024 at JECC Sitapura, in Jaipur. The Pink City has been long known as a treasure trove for ...

橄榄石生日石的保养与清洁 橄榄石 的 莫氏硬度 为 6.5 至 7，比许多宝石都要软，不适合佩戴，因此不建议镶嵌于日常佩戴的戒指中。有些酸性物质（甚至是长期接触酸性汗液）会损坏这种八月生日石。清洁橄榄石是一个非常精细的过程。千万不要使用蒸汽或超声波清洁装置，因为您的橄榄石生日石 ...

When sedimentary carbonate rocks (such as limestones) are geologically transformed by heat and pressure, the calcite and/or dolomite are recrystallized to form a metamorphic rock called marble. When ...

ABSTRACT The published literature offers only a few records of direct measurement of the natural radioactivity in nephrite. The present study used high-purity germanium (HPGe) low-background gamma-ray ...

Figure 1. A 4.56 ct rough diamond with plastic deformation lines, highlighted in the sketch on the right. Deformation has occurred along a set of parallel internal slip planes. The planes appear as ...

Figure 1. Age plot for all the diamond mines that have supplied enough diamonds on which to do age studies. This diagram summarizes all the known diamond growth events through time. Diamond mines ...

Our last three installments of Colored Stones Unearthed have focused on geological processes that form gemstones naturally in the earth. We detailed gemstones formed in magmatic, metamorphic, and ...

Mingora, Pakistan’s earliest emerald mine, was discovered in 1958 (Khan, 2018). Initially, the Mingora, Gujar Killi, Charbagh, and Makhad mines in Swat Valley (figure 3) were explored, mined, and ...

Figure 1. This gold ring with a phoenix motif features a Neyshabur turquoise (13 × 17 mm), with a 0.02 ct ruby on each side and diamond accents. Courtesy of Taktala Jewelry, Tehran. Turquoise is an ...

Figure 1. This cross section through ancient thickened continental lithosphere and underlying mantle shows the two major depth intervals of diamond formation. The majority of mined diamonds originate ...

Aquamarine and heliodor are colored by Fe ions, an important coloring agent for beryl. Blue to yellow gem beryl was studied by quantitative spectroscopy and trace-element analytical techniques to ...