The Stones of the Rio Doce

The following is a brief description of each of the types of stones you may discover while mining with us at the Rio Doce.

Ruby

Ruby has been the world's most valued gemstone for thousands of years. Ruby was said to be the most precious of the twelve stones God created when he created all things and this "lord of gems" was placed on Aaron's neck by God's command. The bible says that wisdom is "more precious than rubies," that is to say very valuable indeed. In the ancient language of Sanskrit, ruby is called ratnaraj, or "king of precious stones" and ratnanayaka, "leader of precious stones."

In fact, rubies are today still more valuable and rare than even the top quality colorless diamonds. A 16 carat ruby sold at auction for US$227,301 per carat at Sotheby's in 1988. A 27.37 carat Burmese ruby ring sold for US$4 million at Sotheby's in Geneva in May 1995, or $146,145 per carat. A 32 carat ruby sold for US$144,000 per carat at Sotheby's in 1989. In contrast, eight D-color internally flawless diamonds over 50 carats were sold in the past 9 years and the largest, a pear-shape of 102 carats, fetched a mere US$125,000 per carat. Top rubies are so rare even the world's top gem dealers must incessantly comb estate sales and auctions to find them. Sizes above five carats are particularly rare.

Ruby is the gem quality of the mineral corundum, one of the most durable minerals which exists, a crystalline form of aluminium oxide. Corundum has a hardness of 9 on the Mohs scale and is also extremely tough. In its common form, it is even used as an abrasive.

Emerald

Because the rich green color of emerald is the color of spring, the ancients prized it as the gemstone symbolizing love and rebirth. Treasured for at least 4,000 years by different cultures all around the world, emerald is said to quicken the intelligence as well as the heart. Legend gives its owner the gift of eloquence.

One legend says that Satan lost the emerald from his crown when he fell. The emerald was shaped into a bowl which the Queen of Sheba sent to Nicodemus. Christ used the bowl at the last supper and Joseph of Arimathea used the bowl to catch blood from the cross, founding the order of the Holy Grail.

Emerald is the birthstone for May, the month of springtime romance, and the anniversary gemstone for the twentieth year of marriage, the perfect emblem of an enduring love.

Emerald is a beryl, a mineral that is normally colorless. Emerald's rich green color is caused by minute traces of chromium. Chromium is the rare Midas element of gemstones: its presence also gives rubies their firey redness. Crystals of emerald grew long before human history in metamorphic rocks, which usually restricts the size of emerald crystals, making them even rarer in large sizes.

Although many people consider Colombia to be the source of the best emeralds, country of origin is never a guarantee of quality. Even the best mine produces mostly low quality gemstones because good qualities are very rare! Fine emeralds also come from Zambia, Brazil, Zimbabwe, Pakistan, Russia and other countries, so don't be afraid to choose the emerald that looks better to you.

As you might expect from gems that have been known to spend centuries at the bottom of the ocean and then return to sell for hundreds of thousands of dollars at auctions, emeralds are durable gemstones with a hardness of 7.5 to 8. However, emeralds with many inclusions should be treated with some care and be protected from blows. With a little care, your emerald will no doubt be treasured by your descendants thousands of years in the future!

Citrine

Citrine is one of the most affordable gemstones, thanks to the durability and availability of this golden quartz. Named from the French name for lemon,"citron," many citrines have a juicy lemon color.

Citrine includes yellow to gold to orange brown shades of transparent quartz. Sunny and affordable, citrine can brighten almost any jewelry style, blending especially well with the yellow gleam of polished gold.

In ancient times, citrine was carried as a protection against snake venom and evil thoughts.

Most citrine is mined in Brazil. Supply of citrine is good from the Brazilian state of Rio Grande do Sul, particularly from the Serra mine, which is producing 300 kilos a month of hammered goods. The Ira’ mine produces an additional 100 kilos a month of hammered goods.

Sometimes you will hear citrine referred to as topaz quartz, which is incorrect. This name was used in the past in reference to the color, which is sometimes similar to the color of topaz. Since topaz is a separate mineral, this type of name can be confusing and should not be used. However, citrine is considered an alternative to topaz as the birthstone for November.

Since most citrine on the market started its life as amethyst which was heated to turn its color to gold, citrine jewelry, as well as amethyst jewelry, should be kept away from prolonged exposure to strong light or heat. With this precaution, citrine jewelry will last for many generations.

Aquamarine

Aquamarine, the "gem of the sea", derives its name from "sea water". The reference is obvious: aqua sparkles like the sea and its color is pale to medium blue, sometimes with a slight hint of green. Aquamarine is the birthstone for March.

Legends say that it is the treasure of mermaids, with the power to keep sailors safe at sea. Aquamarine is said to be a particularly strong charm when immersed in water (which is a good thing, since that is when sailors need its power most!)

Aquamarine is found in Brazil, Zambia, Mozambique, Angola, Nigeria, and other countries.

Aquamarine is always a pastel blue but the darker the color, the more valued it is. Connoisseurs also prefer a pure blue, with no green in it. If you prefer a greenish tinge, you will find that these stones are less expensive.

Because the color is generally pale, aquamarine should have a good clarity. These stones are often cut in ovals and emerald cuts. More saturated colors are unusual in small sizes: usually it takes some size for the color to hold in a darker shade.

Aquamarine is a durable and lively gemstone that is appropriate for all jewelry uses. Its pale fire is flattering to most skin tones.

Rose Quartz

The pale pink color of quartz, which can range from transparent to translucent, is known as rose quartz. The color is a very pale and delicate powder pink. Transparent rose quartz is very rare and is usually so pale that it does not show very much color except in large sizes. The translucent quality of rose quartz is much more available and is used for beads, cabochons, carvings, and architectural purposes.

If you gaze deep inside a crystal ball, you will see a versatile gemstone, one of the most popular gems on earth. Beautiful quartz, the "rock crystal" used in ancient times to make crystal balls and bowls, is today more often seen set in gold jewelry. Despite the popularity of quartz gems like amethyst, citrine, ametrine, rose quartz, onyx, agates, chrysoprase, rutilated quartz, and other quartz gemstone varieties, many people in the jewelry industry take quartz for granted because of its affordable price.

Throughout history, quartz has been the common chameleon of gemstones, standing in for more expensive gemstones ranging from diamond to jade. But the incredible variety of quartz is now beginning to be appreciated for its own sake.

Rutilated Quartz

While most varieties of transparent quartz are valued most when they lack inclusions, some varieties are valued chiefly because of inclusions! The most popular of these is known as rutilated quartz. Rutilated quartz is transparent rock crystal with golden needles of rutile arrayed in patterns inside. Every pattern is different and some are breathtakingly beautiful. The inclusions are sometimes called Venus hair. Less well known is a variety called tourmalinated quartz which, instead of golden rutile, has black or dark green tourmaline crystals.

If you gaze deep inside a crystal ball, you will see a versatile gemstone, one of the most popular gems on earth. Beautiful quartz, the "rock crystal" used in ancient times to make crystal balls and bowls, is today more often seen set in gold jewelry. Despite the popularity of quartz gems like amethyst, citrine, ametrine, rose quartz, onyx, agates, chrysoprase, rutilated quartz, and other quartz gemstone varieties, many people in the jewelry industry take quartz for granted because of its affordable price.

Throughout history, quartz has been the common chameleon of gemstones, standing in for more expensive gemstones ranging from diamond to jade. But the incredible variety of quartz is now beginning to be appreciated for its own sake.

Blue Topaz

Blue topaz is rare in nature, but easily created from clear material. There is an abundance on the world market, and very large, flawless stones are easily available. It is relatively low in value, about the same as good amethyst.. It is available in shades of blue from very light, through sky-blue, and on to almost an inky blue. Overtones of gray are not desirable, and further reduce its value.

The name Topaz is thought to be derived from the name Topazion, the old name for the island of Zebergit (St. Thomas Island) in the Red Sea. The Sanskrit word "Tapas" means "fire". It is insoluble in acids. Some varieties are heat sensitive.

It is a high temperature mineral usually found in igneous rocks and high temperature veins. Also in hydrothermal replacement deposits.

   Blue topaz grew even hotter after 1974. That was the year a San Angelo physicist and his brother, a science teacher, devised a special way to cut topaz. The computer-designed cut creates the image of a perfect five-rayed star in the center of a gem. This “Lone Star cut” was adopted as Texas’ “Official Gem Cut” in 1977.

Tourmaline

Tourmaline's name comes from the Sinhalese word "turmali," which means "mixed." Bright rainbow collections of gemstone varieties were called "turmali" parcels. Tourmaline, occurring in more colors and combinations of colors than any other gemstone variety, lives up to its name. There is a tourmaline that looks like almost any other gemstone! Many stones in the Russian Crown jewels from the 17th Century once thought to be rubies are actually tourmalines.

Perhaps this is why this gemstone is said to encourage artistic intuition: it has many faces and expresses every mood.

Tourmaline is also of interest to scientists because it changes its electrical charge when heated. It becomes a polarized crystalline magnet and can attract light objects. This property was noticed long ago before science could explain it: in the Netherlands, tourmalines were called "aschentrekkers" because they attracted ashes and could be used to clean pipes!

Tourmaline occurs in every color of the rainbow and combinations of two or three colors. Bicolor and tricolor tourmalines, with bands of colors are very popular. Sometimes the colors are at different ends of the crystal and sometimes there is one color in the heart of the crystal and another around the outside. One color combination, pink center with a green rind, is called "watermelon tourmaline" (seedless, of course!) Sometimes designers set slices of the crystal instead of faceted stones to show off this phenomenon.

Almost every color of tourmaline can be found in Brazil, especially in Minas Gerais and Bahia. Pink and green colors are particularly popular. In 1989, miners discovered tourmaline unlike any that had ever been seen before. The new type of tourmaline, which soon became known as Paraiba tourmaline, came in incredibly vivid blues and greens. The demand and excitement for this new material, which soon fetched more than $10,000 per carat, earned more respect for the other colors of tourmaline.

Tourmaline is a hard and durable gemstone which can withstand years of wear. You might want to avoid steam cleaning or heat.

Garnet

The oranges of autumn leaves, the glowing red coals of a winter fire, the sparkling green of a summer field, and the beautiful pinks and of spring flowers, garnet is a gemstone for all seasons. Garnets are a closely related group of gemstones that are available in every color. Dark reds, tangerine orange, vivid lime green, soft bluish-pink, garnet is all these colors and more.

There are garnets that change color in different light, translucent green garnets that look like jade, garnets with stars, garnets that have been mined for thousands of years and garnets that were just discovered in the last decade.

Garnets have long been carried by travellers to protect against accidents far from home. In ancient Asia and the American Southwest, garnets were used as bullets because the glowing red color was said to increase the ferocity of a wound. Garnets in legend light up the night and protect their owners from nightmares. Noah used a garnet lantern to navigate the Ark at night. The ancient world is full of praise for the carbuncle, the glowing red coal of a gemstone we now know as garnet.

The name garnet probably comes from pomegranate. Many ancient pieces of garnet jewelry are studded with tiny red stones that do look a lot like a cluster of pomegranate seeds! Jewelry set with garnets from Czechoslovakia was extremely popular in the nineteenth century and Bohemian garnet jewelry is still popular today, although today the garnets are mined elsewhere. When you say garnet, most people think automatically of small dark red gemstones, even though this is only one aspect of the world of garnets.

Garnet is the birthstone for January, which means that January babies have a lot of choices! Varieties available, some mineral differences and some color descriptions, include rhodolite, malaya, demantoid, grossular, hessonite, spessartite, hessonite, almandine, mandarin, and combinations between these varieties.

Garnets are fairly hard and durable gemstones that are ideal for jewelry use, except for demantoid, which is softer and requires more protection.

Amethyst

Purple has long been considered a royal color so it is not surprising that amethyst has been so much in demand during history. Fine amethysts are featured in the British Crown Jewels and were also a favorite of Catherine the Great and Egyptian royalty. Amethyst, transparent purple quartz, is the most important quartz variety used in jewelry.

Amethyst ranges in color from pale lilac to deep purple. The pale colors are sometimes called "Rose de France" and can be seen set in Victorian jewelry. The deep colors are the most valuable, particularly a rich purple with rose flashes.

Amethyst is mined in Brazil, Uruguay, Bolivia and Argentina, as well as in Zambia, Namibia and other African countries.

Generally, amethyst from South America tends to be available in larger sizes than African amethyst but amethyst from Africa has the reputation for having better, more saturated, color in small sizes. Very dark amethyst, mostly in small sizes, is also mined in Australia.

Amethyst is available in a wide range of calibrated sizes and shapes, including many fancy shapes. Large fine stones may be sold in free sizes but generally amethyst is cut in standardized dimensions.