A new addition to the “Heirloom” collection, this one-of-a-kind piece features 32 custom-cut gemstones.
Precious and imperial topaz from Brazil
Brazil produces more topaz than any other country in the world. Most of the production is colorless, which is irradiated and heated into various shades of blue. Precious and imperial topaz offer a rare and warmer alternative to the cool blue shades we are accustomed to seeing in jewelry stores. “Precious” topaz usually refers to yellow to orange colors while “imperial” topaz usually refers to pinkish-orange to pink to purple and even red colors (see figs. 1 and 6). However, some dealers argue that all topaz in these warmer hues should be classified as imperial. Since the origin of the word topaz is most likely from the Sanskrit word “tapas,” meaning fire, this argument seems to have merit. Recent price increases are due to limited mining, renewed interest from designers in these warmer hues and strong domestic demand in Brazil.
Fig.1: Precious and imperial topaz from Ouro Prêto, Brazil (Gems from 5 carats to more than 62 carats)
Center: Classic orthorhombic crystal with prismatic termination (102g). Photo: E. Boehm, RareSource
No visit to Brazil would be complete without stopping by the famous gold mining region of Ouro Prêto, “Black Gold” in reference to the black rock in which gold was first discovered there during the Brazilian gold rush of the early 18th century. Today, this beautifully preserved colonial Portuguese city is a UNESCO World Heritage Site and the world’s only source for imperial topaz.
Ouro Prêto, while built on gold mining, is today more famous for precious and imperial topaz, which was also discovered here in the early 1700s. The topaz mines are located just a short drive outside the city so it is possible to visit them in a few days. Getting there is easier if one flies through the closest major airport in Belo Horizonte, which is only a two- to three-hour drive from Ouro Prêto.
The two main large-scale mines of Capão and Vermelhão produce the majority of all material on the market today but there are also several small-scale mines operated by independent artisanal miners known as Garimpeiros. Vermelhão is the Portuguese word for vermilion in reference to the reddish-orange to red topaz crystals found there. All the mines are open-pit operations that use water to separate the gem crystals from the weathered host rock.
Fig.2: Washing grate (top left) used for the initial separation of host rock and gem-bearing ore, which flows down the slope to the rolling jig that further separates the gems from the ore. Capão Imperial Topaz Mine, Brazil.
Photo: E. Boehm, RareSource
Fig.3: Fine topaz crystals (top right) displaying the orange to sherry range of color found at the Capão mine in Ouro Prêto, Brazil. Photo: E. Boehm, RareSource
Geology
Topaz is an alumina-silicate that typically forms in granitic pegmatites or rhyolitic igneous rocks. Imagine a molten volcanic material that travels from the lithosphere deep in the earth through the asthenosphere and ultimately into the Earth’s crust. This molten material either migrates up as a large plutonic mass, or squeezes into weaker fractured areas within the earth’s crust creating pegmatites, or explodes out in the form of a volcanic rhyolite. Once it
Fig.5: Topaz crystals in host rock from the Vermelhão Mine in the Saramenha district of Ouro Prêto within the state of Minas Gerais, Brazil. Photo: E. Boehm, RareSource
Gemology
The basic chemical formula for topaz is Al2(SiO4)(F,OH)2. Precious and imperial topaz gets its colors from trace amounts of chromium (Cr+3). It has a relatively high hardness of eight on the Mohs scale, which is the same as spinel. Like diamond, it has one direction of perfect cleavage so care must be taken to avoid hard blows. Its relatively high refractive index (1.61-1.63) and excellent transparency make topaz one of the most versatile and desirable gems. Like tanzanite and chrysoberyl, topaz is no-axial which means it has two optic axes and three optical directions through which light travels at different speeds. These three optical directions represent the three refraction indices of topaz. This also means that each direction has a different absorption producing different colors. Blending these colors in the faceting process is a true art and can produce amazingly varied results, particularly in precious and imperial topaz. Topaz typically contains two-phase inclusions (liquid and gas), three-phase inclusions (crystal, liquid and gas), or multi-phase inclusions (crystals, liquids and gas). These multi-phase inclusions are a result of the hydrothermal phase during which crystal growth occurs.
Graduate Gemologist (G.G.) Edward Boehm is the owner of RareSource (formerly JOEB Enterprises), a Chattanooga, Tenn.-based gemstone supply and consultancy. RareSource travels to mines worldwide to bring customers the finest quality gemstones. Contact him at edward@raresource.com. For those attending the Tucson show next month, please feel free to drop by the RareSource booth #406 at the AGTA show.
The Latest
Last month in Dallas, David Walton pushed another jeweler, David Ettinger, who later died.
The move will allow the manufacturing company to offer a more “diverse and comprehensive” range of products.
With Ho Brothers, you can unlock your brand's true potential and offer customers the personalized jewelry experiences they desire.
From now through mid-May, GIA will be offering the reports at a 50 percent discount.
De Beers’ rough diamond sales were down 18 percent year-over-year in its latest round of sales.
Sponsored by the Las Vegas Antique Jewelry & Watch Show
For over 30 years, JA has advocated for the industry, fought against harmful legislation and backed measures that help jewelry businesses.
The Patek Philippe expert will serve as personal curator for the brand-focused company.
The 553-square-foot shop is aboard the Carnival Jubilee cruise ship.
NDC filed a complaint against Skydiamond for use of phrases like “diamonds made entirely from the sky.”
John Carter received the AGS’s highest honor Tuesday afternoon at Conclave in Austin, Texas.
LVMH said the company performed well despite an uncertain geopolitical and economic environment.
B&D Sales and Service held a ribbon-cutting event for its new location in Cranston, Rhode Island.
It’s ultra-feminine and filled with gold, pearls, and soft pastels.
Emily Highet Morgan and Emily Bennett have joined the agency’s team.
Its updated book for mountings is also now available.
She has been with the organization since 2010, most recently serving as its chief officer of PR and industry relations.
Joyce’s Jewelry sued the bank after cybercriminals drained its accounts of nearly $1.6 million through a series of wire transfers.
He is remembered by loved ones for his loyalty, integrity, and kindness.
Hosted by Freeman’s | Hindman, the sale will take place May 7-8.
The auction house said all 24 timepieces offered in its underground sale of rare and avant-garde watches quickly found buyers.
From lab-grown diamonds and AI to the inevitable Taylor Swift mention, here are some of Conclave’s most intriguing educational offerings.
From cybersecurity liability to trade show coverage, insurance experts share tips on how to build the right policy.
The charm is a modern rendition of the evil eye amulet that has been worn for thousands of years.
Ahead of its trade show next month, TJS awarded free registration and accommodations to one jewelry professional and three students.
By the end of this year, SRK’s diamond manufacturing complexes will achieve net zero emissions, one of an impressive array of achievements.