{"id":11060,"date":"2025-02-21T10:50:10","date_gmt":"2025-02-21T02:50:10","guid":{"rendered":"https:\/\/www.hcenturystar.com\/?p=11060"},"modified":"2025-02-21T11:10:53","modified_gmt":"2025-02-21T03:10:53","slug":"%d9%84%d9%85%d8%a7%d8%b0%d8%a7-%d9%8a%d8%aa%d9%84%d8%a7%d8%b4%d9%89-%d8%a7%d9%84%d8%ad%d8%ac%d8%b1-%d8%a7%d9%84%d8%b7%d8%a8%d9%8a%d8%b9%d9%8a","status":"publish","type":"post","link":"https:\/\/www.hcenturystar.com\/ar\/why-does-natural-stone-fade\/","title":{"rendered":"\u0644\u0645\u0627\u0630\u0627 \u064a\u062a\u0644\u0627\u0634\u0649 \u0627\u0644\u0644\u0648\u0646 \u0641\u064a \u0627\u0644\u0623\u062d\u062c\u0627\u0631 \u0627\u0644\u0637\u0628\u064a\u0639\u064a\u0629\u061f"},"content":{"rendered":"\n

Over the long history of human civilization, natural stone has consistently been regarded as a priceless gift in the fields of art and building. This has been the case during whole human history. Because of its unique texture, good temperance, and amazing physical qualities, marble has come to represent high-end building and creative expression. Marble is a substance with all these attributes. This can be seen in the seriousness of the Pantheon in ancient Rome as well as in the Renaissance figures Michelangelo produced with such finesse. Still, the passage of time leaves traces of its existence always. Many marble objects have progressively lost their former magnificence with time, which has inspired people to consider the lifetime of stone carefully. This has inspired the creation of some fascinating concepts.<\/p>\n\n\n\n

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\"blue<\/a>
blue granite slab<\/figcaption><\/figure>\n\n\n\n
\"Blue<\/a>
Blue Emerald Granite<\/figcaption><\/figure>\n<\/figure>\n\n\n\n

1. Formation mechanism of mineral color<\/strong><\/strong><\/h3>\n\n\n\n

Mineral colors are akin to those of a vibrant picture; behind them lie intricate scientific ideas. Minerals’ colors can be separated as autochromatic and heterochromatic. Whereas heterochromatic is the color of the mineral resulting from the presence of colored impurities, which has nothing to do with the nature of the mineral, autochromatic is the inherent color of the mineral itself. For instance, pure quartz is colorless and transparent; but, if manganese oxide is added in small quantities, it will be colored black or smoky, producing the known smokey quartz. This color shift is like nature embedding vibrant seeds in the mineral; as the surroundings alter, these seeds silently blossom and display changing colors.
Apart from the effect of contaminants, the internal cleavage or fissures in the oxide film on the surface of the mineral will also create interference of light waves, therefore producing misleading colors. An ordinary example is calcite. The cleft surface’s developed reflectance and interference with light will create a halo like to a rainbow. This halo lets minerals reveal erratic colors under various light, like a secret veil handed to them by nature.
These ideas provide the foundation of stone’s coloring technologies and color changing. People can give stones a brand-new hue by adding dyes or altering the surface structure of minerals, hence coating stones. This method not only meets people’s want of beauty but also creates more area for the usage of stones.<\/p>\n\n\n\n

2. The cause of the color of some decorative stones<\/strong><\/h3>\n\n\n\n
\"green<\/a>
green quartzite slab\u200b\n\n<\/figcaption><\/figure>\n\n\n\n

Unlike minerals, the color development mechanism of rocks is more complex and usually results from the combined activity of several elements. For instance, light gray to almost black marble could have different levels of organic content and finely scattered heavy metal sulfides (mostly iron, then copper, aluminum, etc.). These elements are like a “palace” hidden in the stone, lending the stone varying colors. Typical ones are “Guilin Black” in Guangxi, “Crystal Black” in Zhijin, Guizhou, “Suzhou Black” in Jiangsu, “Moyu” in Huolu, Hebei, and “Dalian Black” in Liaoning. Most of these stones are carbonaceous or asphaltene, among which “Guilin Black” will volatilize a sulfide smell during processing and a thin film of oil will float on the stone slurry. On the polished board surface, occasionally designs akin to fossil leaves or ferns will show up.
Typical hydrates of iron oxide found in red, maroon, purple, brown and yellow stones are hydrohematite, hematite, hydrohematite and limonite. These minerals give the “Red Wanluo” marble from Lingbi, Anhui Province, its red color. Usually, purple stone results from the presence of manganese oxide and iron oxide in a specific ratio, as the “Purple Bean Ban” marble from Huolu, Hebei Province does.
Usually connected to low-valent oxides of iron and silicon-magnesium compounds, such as glauconite, chlorite, serpentine, amphibole, diopside, olivine, garnet and actinolite, the creation of green and grass green stone is more complex. Sometimes the stone seems green because of copper or compounds as well. Serpentine is mostly responsible for the green marbles including “Jinyu” from Changping, Beijing, “Clouds” from Huolu, Hebei, “Dandong Green” from Liaoning, “Laiyang Green” from Shandong, and “Diecui” from Zhenghe, Fujian Province. Serpentine’s chemical formula is Mg\u2086Si\u2084O\u2081\u2080\u2088. It might include variations including FeO, Fe\u2082O\u2083, NiO, etc. Usually in dense blocks, it features a range of green tones including dark green, dark green, yellow-green, light green, and so on. The name “serpentine” comes from the surface’s blue-green marks like those of snake skin.
Granite’s color is mostly defined by the hue of its rock-forming minerals. Granite consists fundamentally in quartz, feldspar, amphibole, pyroxene, olivine, and biotite. Among them, quartz and feldspar are light-colored minerals; the stone color is lighter when the quantity of black minerals is less than 1%; white granite will thus be produced, as the “Lotus White” in Fenyi, Jiangxi. Granite’s hue will progressively darken as the content of dark minerals rises, creating a gray or gray series including the “Quanzhou White” in Fujian and the “Sesame Gray” in Huanggang, Hubei. Granite will show a darker tone, such “Jinan Blue” and “Fengzhen Black,” when the dark minerals expand farther.
Granite’s color is largely influenced by the form of feldspar. Plagioclase generally gives the stone a white appearance; so, when the plagioclase content is considerable, the rock will seem gray or gray in several tones, such “Huanggang Gray”. This type of granite is more precious as the content of labradorite in granite grows will exhibit blue, green, purple, golden and other hues in a certain direction. As the potassium feldspar level rises, the stone will seem pink or crimson, like to “Taoyuan Red”. Most of the red stones found both domestically and internationally are this kind.
Furthermore influencing the hue of the rock will be its dryness and dampness. In the wet condition the color is darker; in the dry condition it is lighter. To thereby differentiate the color, mineral composition, and structural structure of the stone, stone professionals may employ moist water. Furthermore influencing the color will be varying degrees of polishing; the mirror polished surface is darker and the rough surface is lighter. Additionally important is the freshness of the rock; the hue of the aged stone is lighter while the fresh stone is darker. Usually, the color of the face stone we discuss is the color obtained after polishing.<\/p>\n\n\n\n

3. Factors causing stone to fade. <\/strong><\/h3>\n\n\n
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\"green<\/a>
green onyx gemstone\u200b\n\n<\/figcaption><\/figure>\n<\/div>\n\n\n

Fading in Marble<\/strong>
Marble, the ancient and well-known stone aristocracy, has lost its former majesty over the years; what can have led to this? The main constituents of this material are calcite ( CaCO3) and dolomite ( CaMg(CO3), the “culprits” of fading.The fast reaction between very active carbonate ions [CO2] and sulfur dioxide gas in the environment generates gypsum (CaSO2H2). This gypsum produces turbid particles connected to the surface of the stone. These particles seem like a layer of gray veil covering the marble’s natural brilliance. Calcite is also readily reacted with water to produce water-soluble calcium bicarbonate [Ca(HCO2), which would subsequently change into calcium carbonate (calcite) as the water evaporates. In places marked by limestone, this mechanism is in charge of the development of caverns, stalactites, and stalagmites. Marble used outside will fade really greatly and become much less bright after two to three years of exposure to wind and rain.
Apart from chemical processes, a long “contest” between the stone and the surrounding natural habitat is causing degradation of the stone. These natural components\u2014the blazing sun, the scouring rain, the erosion of wind and sand\u2014are like merciless artists changing the look of marble gradually. The chemical reaction on the surface of the stone accelerates under UV radiation, which eventually fades the hue. The acidic components of acid rain interact with the calcium carbonate in the marble to hasten the fade of the color. The physical wear and tear from wind and sand causes the sheen of the marble surface to progressively fade, so the color gets less vivid.
The narrative of marble losing appeal has been told for a very long period in the lengthy and remarkable history of human civilization. Long since lost its bright whiteness due to the passage of time, the Pantheon in ancient Rome is regarded as an architectural wonder spanning more than two thousand years. During the Renaissance, which spans several hundred years, many Michelangelo’s marble works changed in surface hue. These fading events affect not only the value of artistic creations but also inspire people to consider ways in which they could protect priceless cultural treasures by means of preservation initiatives.
D<\/strong>egradation <\/strong>O<\/strong>f <\/strong>G<\/strong>rass<\/strong>
Granite seems to have more “anti-aging” impact than marble. Mostly consisting of igneous rock elements including feldspar, quartz, pyroxene, amphibole, mica, and other components, granite is a form of rock. Each silicon ion in the structure of these silicate minerals is surrounded by four oxygen ions, therefore producing a silicon-oxygen tetrahedron\u2014the basic structural unit of silicates. Weathering is highly resisted; it is somewhat stable; it resists acid; it is tough to dissolve. Granite interacts with the acid in the air less easily than marble does, which produces cloud-like gypsum particles that stick to the surface and fade the material.
Still, rocks are not an exception; nature does not have any completely stable object. Apart from granite, erosion affects even the highest mountains. Minerals make up rocks; heated water and the process of weathering will cause minerals to start to change into other secondary minerals. Feldspar, mica, and amphibole will become kaolin or limonite; pyroxene will usually change into epidote; chlorite or calcite will finally change into olivine; and serpentine or magnesite will develop from olivine. These modifications will definitely affect the color of the rock; nonetheless, this process takes a lot of time and some of the changes are almost beyond human comprehension. Actually, the color of granite might have altered for a number of different reasons before these mineral adjustments.<\/p>\n","protected":false},"excerpt":{"rendered":"

Over the long history of human civilization, natural stone has consistently been regarded as a priceless gift in the fields of art and building. This has been the case during whole human history. Because of its unique texture, good temperance, and amazing physical qualities, marble has come to represent high-end building and creative expression. Marble […]<\/p>\n","protected":false},"author":9,"featured_media":11117,"comment_status":"closed","ping_status":"closed","sticky":false,"template":"","format":"standard","meta":{"footnotes":""},"categories":[36,35,34],"tags":[7422,7421,7424,7423],"class_list":["post-11060","post","type-post","status-publish","format-standard","has-post-thumbnail","hentry","category-knowledge","category-blogs","category-news","tag-blue-emerald-granite","tag-blue-granite-slab","tag-green-onyx-gemstone","tag-green-quartzite-slab-2"],"acf":[],"_links":{"self":[{"href":"https:\/\/www.hcenturystar.com\/ar\/wp-json\/wp\/v2\/posts\/11060","targetHints":{"allow":["GET"]}}],"collection":[{"href":"https:\/\/www.hcenturystar.com\/ar\/wp-json\/wp\/v2\/posts"}],"about":[{"href":"https:\/\/www.hcenturystar.com\/ar\/wp-json\/wp\/v2\/types\/post"}],"author":[{"embeddable":true,"href":"https:\/\/www.hcenturystar.com\/ar\/wp-json\/wp\/v2\/users\/9"}],"replies":[{"embeddable":true,"href":"https:\/\/www.hcenturystar.com\/ar\/wp-json\/wp\/v2\/comments?post=11060"}],"version-history":[{"count":0,"href":"https:\/\/www.hcenturystar.com\/ar\/wp-json\/wp\/v2\/posts\/11060\/revisions"}],"wp:featuredmedia":[{"embeddable":true,"href":"https:\/\/www.hcenturystar.com\/ar\/wp-json\/wp\/v2\/media\/11117"}],"wp:attachment":[{"href":"https:\/\/www.hcenturystar.com\/ar\/wp-json\/wp\/v2\/media?parent=11060"}],"wp:term":[{"taxonomy":"category","embeddable":true,"href":"https:\/\/www.hcenturystar.com\/ar\/wp-json\/wp\/v2\/categories?post=11060"},{"taxonomy":"post_tag","embeddable":true,"href":"https:\/\/www.hcenturystar.com\/ar\/wp-json\/wp\/v2\/tags?post=11060"}],"curies":[{"name":"wp","href":"https:\/\/api.w.org\/{rel}","templated":true}]}}