Mineral crystals are rare resources with both scientific research and ornamental value. They are natural, unique, exquisite, precious and non-renewable works of art given by nature. They are favored by people for their peculiar crystal shape, various shapes and gorgeous colors. The collection of mineral crystals has a history of more than 100 years in Western countries and has been circulated all over the world. With the development of China’s economy and the deepening of international cultural exchanges, the trend of the popularization of mineral crystal knowledge and the collection of specimens has gradually emerged.
Mineral collection basics
First of all, because mineral types and mineral collections require a lot of basic knowledge reserves of geology, mineralogy and crystallography. This knowledge is used in many ways, such as when collecting mineral specimens in the wild, when purchasing mineral specimens, and when communicating with collectors. Identify the type of mineral and identify whether the mineral is a synthetic mineral or whether it is a processed mineral. If you are interested in radioactive minerals, expertise in the storage of radioactive minerals is essential.
Minerals are the products of various geological processes in the earth’s crust, and are natural elemental elements or natural compounds formed by various elements naturally existing in the earth’s crust with fixed chemical composition and physical and chemical properties, of which compounds are mainly, and most of them are crystals.
Mineral crystals generally refer to many mineral single crystals growing in the cracks or voids of rocks and the clusters they consist of. In nature, minerals produced in intact single crystals or crystal clusters are relatively rare, and because the complete development of crystals requires a good space for free growth, they are generally found in geode cracks.
The mineral formation mode is mainly gaseous crystal, such as natural sulfur crystal; Liquid crystals, such as all kinds of magma minerals, or rock salt and gypsum crystallized in solution (salt lake); Solid crystal conversion, such as aragonite into calcite, β quartz into α quartz, also formed by intermineral metasomatism, such as calcite metasomatism fluorite, forming the illusion of fluorite.
Minerals are classified according to their chemical composition into five main categories: natural elements, sulfides and similar compounds, oxides and hydroxides, oxy-containing salts, and halides. Most mineral collectors want to collect more minerals.
The crystalline forms of minerals can be divided into monomorphic and polygonal. A simplex is the sum of a set of crystal faces connected by symmetrical elements. During the actual growth of crystals, due to the influence of the growth environment, although the same physical and chemical properties are retained, the shape of the geometric polyhedron is often distorted, forming a distorted crystal with a non-ideal shape. The crystal contains 47 kinds of monomorphisms, which belong to three major classes and seven crystal systems. A polyform is a crystalline form formed by the meeting of two or more monomorphs. There are as many kinds of monomorphs together as there are many kinds of crystal faces on the cluster, their properties are different, and only monomorphs of the same symmetrical type can form a cluster.
Direction of mineral collection
There are many directions of mineral collection, mineral collection in addition to the need for rich knowledge reserves, but also need to consume a lot of energy, financial resources, the vast majority of collectors generally choose a main collection direction, of course, see the favorite minerals will also collect some other.
- Mineral varieties
Collecting various varieties of minerals has always been the purpose and dream of the majority of mineral collectors, at present, there are more than 4,500 kinds of minerals discovered by humans, and there are about 300 kinds of common minerals, and many collectors can only collect more than 200 kinds in their lifetime. Collecting many varieties of minerals takes a lot of time, effort and money. Not only do you need to go to various exhibitions, mining areas and mining areas, but some rare minerals also need to be exchanged between collectors.
Second, a single type of mineral
The direction of a single kind of mineral collection is generally to collect different colors, inclusions, crystal shapes, parallel connected, twin crystals, floating, aggregate forms, surrounding rocks, origin and associated minerals of the same mineral. Collectors who are generally interested in this direction will choose some large, more common and more complex mineral types, such as crystal, fluorite, calcite, gypsum, garnet, feldspar and so on.
- Gemstone minerals
Gemstone minerals are the most eye-catching for their gorgeous colors and are also loved by the majority of collectors. Another important aspect of the gem mineral collection is the characteristics of the various places where the gems are collected, such as the red beryl produced in rhyolite, the Dabiz effect in the emerald of Colombia, and the horsetail inclusion in the emerald of the Urals.
- Mineral crystal form and aggregate form
There are many kinds of crystal forms and production forms of minerals, such as monomorphic, polycrystalline, twinning, polycrystalline association, crystal clusters, etc. The aggregate forms are tuberculous, radial, granular, sheet, plate and so on.
5.the color of minerals
Minerals have many colors, everyone has a favorite color, and will relatively prefer minerals with this color.
- Metallic elemental minerals
Metallic elemental minerals generally have natural gold, natural silver, natural copper, natural platinum, natural osmium, natural bismuth and so on.
- Metallic minerals
Metal minerals generally refer to the minerals used for refining metals, such as hematite, magnetite, limonite, etc. Copper malachite, azurite, chalcogenite, etc.; Lead ore class of white lead ore, arsenic lead ore, phosphorus chloride lead ore, etc.
- Fluorescent and phosphorescent minerals
Some minerals have unique luminescence, the mineral itself or mineral inclusions have the nature of emitting different colors of light under ultraviolet light, collectors love this characteristic and collection, in addition to radioactive minerals, common fluorescent minerals are fluorite, calcite, gypsum, opal (jade drop stone), white lead, scheelite, calcite, diamond and so on.
9.Radioactive minerals
Although radioactive minerals may have a certain impact on the health of collectors, some collectors collect them because of their gorgeous colors, unique crystal shapes, and the strong and gorgeous fluorescence of most radioactive minerals under ultraviolet light. Collectors of radioactive minerals generally have special collection rooms and storage cabinets and boxes, as well as light sources and observation boxes for observing fluorescence.
Evaluation of mineral specimens
The ornamental and specimen properties of mineral crystals are evaluated from three aspects: first, rarity; Second, the color, luster and transparency of mineral crystals; The third is the form, combination and integrity of minerals.
Rarity is divided into the rarity of mineral varieties, the rarity of form, the rarity of molding, the rarity of color, the rarity of crystal size, and the rarity of symbiotic combinations.
- Rarity of the variety
The amount of different minerals produced in the crust varies greatly, such as common calcite, crystal, fluorite, mica, etc. Some minerals are relatively rare, such as chlorophenite, cassiterite, rhombosite and so on.
A mineral often has a variety of close forms, some relatively common, some rare or even rare. For example, diamond-dodecahedral fluorite and trioctahedral polygonal fluorite are rarer than cubic fluorite, and octahedral pyrite is rarer than cubic pyrite.
- Rarity of form
Twinning minerals are rare. Such as wheeled twin chrysoberyl and white lead ore; Dovetail twin gypsum and calcite; Japanese twin crystal, Brazilian twin crystal, Dauphin twin crystal and so on.
- Forming rarity
Some minerals have more idiomorphic or semi-idiomorphic crystals, such as garnet and tourmaline. Some minerals form less regular crystals, such as olivine and rosacene.
- Rarity of color
The same mineral can come in many colors, some common and some uncommon. For example, purple quadrigalites are less common than yellow quadrigalites, and green axolites are more common than brown axolites.
- Rarity of crystal size
The crystal size of the same mineral reflects the degree of crystallization of the crystal, in general, the larger the size, the rarer, especially for rare minerals. For example, the rhododendron ore stored in the Geological Museum of Hunan Province – “Queen of China”, and the “Crystal King” stored in the Geological Museum of China.
- Rarity of symbiotic association
Different minerals often live together in symbiosis, and there are many common combinations. Such as malachite and azurite symbiosis, fisheye and zeolite symbiosis, beryl and mica symbiosis. The uncommon symbiotic relationship has not only collection value, but also important scientific research value. Such as cassite, beryl, apatite, Muscovite symbiotic combination.
In terms of color, gloss and transparency, the brighter the color, the better; The stronger the gloss, the better; Transparency is generally the more transparent the better, but a mineral may have a special luster due to its inclusions, such as the fibrous inclusions of chrysoberyl.
The form, combination and integrity of mineral specimens are evaluated from the whole of the specimen.
The more typical and standard the crystal form, the better. But sometimes there will be distorted crystals, corrosion, or other crystals with natural defects, their shape is strange, relatively rare, and can also have a high value. For example, Zimbabwe produces “Star Diamond”, Pakistan produces dissolved beryl and crystal.
The combination of specimens, a specimen obviously has a variety of larger mineral crystals is relatively rare, usually has a variety of minerals and has different colors, the composition of the specimen has a gorgeous appearance and high value. Such as Tianhe stone and smoke crystal symbiosis; Scheelite, wolframite, fluorite, calcite symbiosis.
The integrity of crystals refers to the degree to which they remain intact during mining, handling, processing and distribution. For single crystals, the integrity of crystal form is very important, the more complete the better.