直到20世纪90年代,矿物学家才能提出在人造物质分解过程中形成的化合物的名称……在工业​​污泥坑和生锈汽车等地方发现的东西。这个漏洞现在已经关闭,但书上的矿物质并不是真正自然的。传统上和正式地,天然汞被认为是矿物质,即使金属在室温下是液体。然而,在约-40℃时,它凝固并形成与其他金属一样的晶体。因此,南极洲的部分地区的汞是无可比拟的矿物质。对于一个不太极端的例子,考虑矿物ikaite,一种仅在冷水中形成的水​​合碳酸钙。它在8℃以上降解成方解石和水。它在极地地区,海底和其他寒冷的地方都很重要,但除了在冰箱外,你不能把它带进实验室。冰是矿物质,即使它没有在矿物领域指南中列出。当冰收集在足够大的物体中时,它会以固态流动 – 这就是冰川所在的状态。盐(岩盐)表现相似,在宽阔的圆顶中上升,有时在盐冰川中溢出。事实上,所有矿物质和它们所属的岩石,只要有足够的热量和压力,就会慢慢变形。这就是板块构造成为可能的原因。所以从某种意义上说,除了钻石之外,没有任何矿物质是真正的。其他不太坚固的矿物质则是灵活的。云母矿物是最着名的例子,但辉钼矿是另一个。它的金属片可以像铝箔一样皱折。石棉矿物温石棉具有足够的粘性,可以编织成布料。矿物质必须是无机的规则可能是最严格的规则。例如,构成煤的物质是来自细胞壁,木材,花粉等的不同种类的烃化合物。这些被称为macerals而不是矿物质(更多信息,请参见坚果壳中的煤)。如果煤被足够长时间地挤压,那么碳就会脱掉所有其他元素并变成石墨。即使它是有机来源的,石墨也是真正的矿物质,碳原子排列成片状。类似地,钻石是排列在刚性框架中的碳原子。在地球上生存了大约40亿年之后,可以肯定地说,即使世界上的钻石和石墨都不是有机的,它们也是有机的。结晶度有些不足,我们尝试的时候很难。许多矿物质形成的晶体太小,无法在显微镜下看到。但是,即使这些也可以使用X射线粉末衍射技术在纳米尺度上显示为结晶,因为X射线是超短波类型的光,可以成像非常小的东西。具有晶形意味着该物质具有化学式。它可能像halite(NaCl)或复合物如绿帘石(Ca2Al2(Fe3 +,Al)(SiO4)(Si2O7)O(OH))一样简单,但如果你缩小到原子的大小,你可以分辨出你是什么矿物质通过其分子构成和安排来看待。一些物质未通过X射线测试。它们是真正的玻璃或胶体,在原子尺度上具有完全随机的结构。对于“无形”,它们是无定形的,科学的拉丁语。这些获得了名字mineraloid。 Mineraloids是一个由大约八个成员组成的小型俱乐部,通过包含一些有机物质(违反标准3和4)来扩展事物。在Mineraloids画廊中看到它们。

加拿大渥太华大学地质学Essay代写: 矿物质

Until the 1990s, mineralogists could propose names for chemical compounds that formed during the breakdown of artificial substances…things found in places like industrial sludge pits and rusting cars. That loophole is now closed, but there are minerals on the books that aren’t truly natural. Traditionally and officially, native mercury is considered a mineral, even though the metal is liquid at room temperature. At about -40 C, though, it solidifies and forms crystals like other metals. So there are parts of Antarctica where mercury is unimpeachably a mineral. For a less extreme example, consider the mineral ikaite, a hydrated calcium carbonate that forms only in cold water. It degrades into calcite and water above 8 C. It is significant in the polar regions, the ocean floor, and other cold places, but you can’t bring it into the lab except in a freezer. Ice is a mineral, even though it isn’t listed in the mineral field guide. When ice collects in large enough bodies, it flows in its solid state — that’s what glaciers are. And salt (halite) behaves similarly, rising underground in broad domes and sometimes spilling out in salt glaciers. Indeed, all minerals, and the rocks they are part of, slowly deform given enough heat and pressure. That’s what makes plate tectonics possible. So in a sense, no minerals are really solid except maybe diamonds. Other minerals that aren’t quite solid are instead flexible. The mica minerals are the best-known example, but molybdenite is another. Its metallic flakes can be crumpled like aluminum foil. The asbestos mineral chrysotile is stringy enough to weave into cloth. The rule that minerals must be inorganic may be the strictest one. The substances that make up coal, for instance, are different kinds of hydrocarbon compounds derived from cell walls, wood, pollen, and so on. These are called macerals instead of minerals (for more, see Coal in a Nutshell). If coal is squeezed hard enough for long enough, the carbon sheds all its other elements and becomes graphite. Even though it is of organic origin, graphite is a true mineral with carbon atoms arranged in sheets. Diamonds, similarly, are carbon atoms arranged in a rigid framework. After some four billion years of life on Earth, it’s safe to say that all the world’s diamonds and graphite are of organic origin even if they aren’t strictly speaking organic. A few things fall short in crystallinity, hard as we try. Many minerals form crystals that are too small to see under the microscope. But even these can be shown to be crystalline at the nanoscale using the technique of X-ray powder diffraction, though, because X-rays are a super-shortwave type of light that can image extremely small things. Having a crystal form means that the substance has a chemical formula. It might be as simple as halite’s (NaCl) or complex like epidote’s (Ca2Al2(Fe3+, Al)(SiO4)(Si2O7)O(OH)), but if you were shrunk to an atom’s size, you could tell what mineral you were seeing by its molecular makeup and arrangement. A few substances fail the X-ray test. They are truly glasses or colloids, with a fully random structure at the atomic scale. They are amorphous, scientific Latin for “formless.” These get the honorary name mineraloid. Mineraloids are a small club of about eight members, and that’s stretching things by including some organic substances (violating criterion 3 as well as 4). See them in the Mineraloids Gallery.

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