When it comes to Canada, the first thing that comes to mind is the maple leaves that fall with the wind in late autumn. However, Canada's beauty is not limited to that.
In Canada, there is a gemstone that can be called the only one in the world. It emits colorful light, as if it were the embodiment of a rainbow. It shows people its complete body and fine texture. It is Canada's national treasure - the spotted stone.
<h1 class="pgc-h-arrow-right" > new member of the gem family</h1>
Hundreds of years ago, locals living on the St. Mary's River in Alberta, western Canada, accidentally found several colored stones in the rocks. This stone emits a colorful light in the sun, and if you turn the stone, its color will also change accordingly, which is strange. At that time, people believed that the stone absorbed the essence of heaven and earth and had magical powers, so they wore it as a "sacred stone".
In 1908, scientists from the Canadian Geological Survey came to the banks of the St. Mary's River. This rainbow-like unique rock first appeared in geologists' field of vision, but it was not studied in depth at the time. In 1962, at a small jewelry show in Alberta, Canada, the stone was displayed on jewelry. Unfortunately, people don't know it, or even its name. In 1967, a clever jewelry store owner gave it a beautiful name: Zephyrite. As a result, zebra began to become popular. Fourteen years later, the World Jewelry Federation officially recognized it as a new type of gemstone, and spot color stone began to be commercially developed and sold. There is also one newest member of the colored gem family.
The appearance of every new thing always attracts curious eyes. The emergence of zebra caters to young people's pursuit of novelty fashion. When diamonds, gold, and jadeite dominate the jewelry market, zebra attracts more and more young consumers with its new name, unique colors and stylish designs.
<h1 class="pgc-h-arrow-right" > the embodiment of a rainbow of seven colors</h1>
At present, the international evaluation criteria for zebra are very simple. Gemstones with a strong rainbow color that change color from different angles are high-quality gemstones. So, how is the colorful color of the zebra stone formed?
Geologists have found that the surface of the zebra stone has only a thin layer of color effects. Its thickness is generally 0.5-0.8mm, basically not more than 1mm. Its color and brightness depend directly on the thickness of this layer. The thicker ones are mainly red and green, while the thinner ones are mainly blue and purple. We know that the color of gemstones such as rubies and sapphires is due to the absorption of specific light by white light, while the seven colors of zebra stone come from the interference of internal microstructure with light.
Not only is the color of the zebraite bright, but the surface cracks are also unique. When formed underground, the pressure on the overlying rock layers is uneven, creating a criss-crossing texture on the surface of the mottled stone, with colors and aesthetics like fish scales.
Although the zebra stone is beautiful, it has a very serious flaw, and that is that it is too soft. Its Mohs hardness is only 3.5-5.5, which is slightly harder than a human fingernail. If you scrape it gently with a knife, it will be damaged. It can be seen that it is not appropriate to use it directly as jewelry. Moreover, when exposed to air for a long time, its color will gradually darken due to the oxidation of the air.
To solve these problems, jewelers have tried various methods to effectively protect them. The usual practice is: for large exhibits, coat its surface with a special transparent colloid, isolate the air, prevent oxidation, and try to maintain the original state of the fossil; for the spot color stone as a small ornament, after cutting, the front and back of the spot color stone are added to the protective layer, the front is covered with transparent quartz or spinel, and the hardness is increased to 7-8. After this treatment, the hardness of the gemstone is greatly improved, and it can resist the collision of most objects. Black shale or other materials are fixed to the back of the porphyry and act as a double protector.
<h1 class= "pgc-h-arrow-right" > fossils of ancient creatures</h1>
If you are lucky enough to see the entire zebra stone, you will find that its silhouette resembles that of modern marine life, the Nautilus. It was found that the porphyllite was actually a fossil of a paleontology called "ammonite". Ammonite is a marine invertebrate. It comes with a spiral shell. The general length is 0.25-0.5 meters, and a few can exceed 1 meter. In the early Mesozoic Era, this creature flourished, but eventually went extinct almost at the same time as the dinosaurs.
The main component of zebra is aragonite, or calcium carbonate, similar to pearls. The difference between the two is that the porphyllite is formed by tens of millions of years of geological action in nature, while pearls are formed organically.
Although prehistoric ammonites are found almost everywhere in the world, only the eastern slopes of the Canadian Rockies and a small isolated area of southwestern Alberta have formed gem-quality porphyry and achieved commercial production. 70-75 million years ago, the Rocky Mountains of North America rose slowly. At that time, the eastern part of the hillside was still a vast ocean, inhabited by a large number of marine life, including ammonites, shellfish, turtles and other marine life. Due to the continuous erosion of the Rocky Mountains by rainfall, large amounts of sediment were washed into the sea along the river, and dead ammonite corpses were buried by sediment. After more than 70 million years of tectonic movement and suitable temperature, pressure and other conditions, the partially buried ammonite body finally formed a unique porphyrite.
< h1 class="pgc-h-arrow-right" > facing extinction again</h1>
As the saying goes, "things are more expensive than rare". Although zebra is a new product, the production is extremely limited. In the mining area, the formation thickness of the porphyry layer is only one or two meters, and the formed porphyry layer is inclined, making it difficult to mine. Sadly, many of the porphyry stones have been destroyed by natural weathering.
In addition, current ore mining methods are similar to open-pit coal mines. People use excavators to directly peel off the overlying rock layers, causing great damage to the local ecological environment. Therefore, the local ore mining is strictly restricted. As a result, the number of true porphyry is small, and there are few complete fossil specimens. On September 27, 2007, the American Museum of Natural History exhibited a 0.6-meter-long porphyry stone. It is not only beautiful in appearance, but also has important research value. The study of North American paleontology and paleoclimate is of great significance to geologists. A treasure.
In general, porphyry is usually found in gray-brown shale, marl and limestone, but its composition is not exactly the same. In addition to the main component, aragonite, some porphyry also contains calcite, quartz, and even pyrite. When there is pyrite near the ammonite fossil burial area, the calcium in it may be gradually replaced by pyrite, thus forming pyrite fossils. Although the fossil is still the shell of ammonite, it has a bright metallic luster. Although geologists have found a small number of similar fossils in other parts of the world, such as Utah, Madagascar and Morocco in the United States, their color layers are too thin and not bright enough to be gemstones compared to those in Canada.
Experts estimate that Canada's current copper mining capacity will reach about 20 years. If no new source is found in the future, the zebra will be like the ammonite of prehistoric times, "extinct again".