There are 9 important physical properties of minerals:
- Hardness
- Luster
- Color
- Streak
- Specific Gravity
- Cleavage
- Fracture
- Tenacity
- Crystal System
What are six special properties of minerals?
- fingernail- 2 to 2.5 on the Mosh scale
- Copper penny or house wire-3 on the Mosh scale
- Glass-5.5 on the Mosh scale
- knife-5.5 to 6 on the Mosh scale
- Steel file-6.5 on the Mosh scale
- Streak plate (unglazed ceramic tile)- 6.5 to 7 on the Mosh scale
What determines Meany physical properties of minerals?
- You can identify a mineral by its appearance and other properties.
- The color and luster describe the appearance of a mineral, and streak describes the color of the powdered mineral.
- A mineral has a characteristic density.
- Mohs hardness scale is used to compare the hardness of minerals.
Which properties are used to identify minerals?
- Colour
- Texture
- Density
- Luminescence
- Crytallography
- Magnetism
- Chemical reaction to acid
- Smell
- Morphology
- Irradescence
Which determines the chemical properties of minerals?
What determines the chemical properties is : color, hardness, luster, crystal forms, density, and cleavage.
What are the physical properties of minerals?
The physical properties of minerals include name, crystal system, color as it appears to the naked eye, streak by rubbing on streak plate, luster, hardness on the Mohs scale, and average specific gravity. The chemical properties comprise chemical formula and the proportion of elements in the purest form of the minerals.
What are chemical properties?
The chemical properties comprise chemical formula and the proportion of elements in the purest form of the minerals. The information base extends with short description of mode of occurrences, and major uses of the metals and minerals. This has briefly been tabulated in ( Table 1.1) for ready reference.
What are some examples of mineraloids?
It usually occurs by excretion of minerals substances from the edge to the center of fissures of almost any kind of rock, being most commonly found with basalt, rhyolite, limonite, sandstone and marl.
Is a crystallized mineral anisotropic or isotropic?
They are anisotropi c. Minerals which are part of the cubic system and amorphous solid are isotropic which means that light behaves the same way no matter which direction it is traveling in the crystal. The isotropy and anisotropy of crystallized minerals will be discussed in more detail in Sections 2.2.3 and 2.3.2.
Do crystallized minerals have a constant melting point?
Crystallized minerals have specific and constant physical properties. Same minerals always have a constant melting point or crystallization point. If we increase the temperature of crystallized mineral, when it reaches melting point, it will stop to heat as long as the mineral does not convert to mineral melt.
Isotropism
Minerals are grouped according to their physical properties, which may be direction dependent.
Anisotropic
In a single crystal, the physical and mechanical properties often differ with orientation. It can be seen from looking at our models of crystalline structure that atoms should be able to slip over one another or distort in relation to one another easier in some directions than others.
Isotropic
Alternately, when the properties of a material are the same in all directions, the material is said to be isotropic. For many polycrystalline materials the grain orientations are random before any working (deformation) of the material is done.
Polymorphism
Physical properties of minerals are directly related to their atomic structure, bonding forces and chemical composition. Bonding forces as electrical forces exist between the atoms and ions are related to the type of elements, and the distance between them in the crystalline structure.
I. Cohesion and Elasticity
Cohesion: The force of attraction existing between molecules. It shows resistance to any external influence that tends to separate them, eg., breaking or scratching the surface of a solid mineral. Cohesion force is related to bonding force.
II. Specific Gravity
Specific gravity (SG) or relative density is a unitless number that expresses the ratio between the weight of a substance and the weight of an equal volume of water at 4degree (max ρ).
III. Light
Diapheneity is amount of light transmitted or absorbed by a solid.Diapheneity generally used strictly for hand specimens also most minerals opaque in hand specimens and transparent in thin sections
What are the physical properties of minerals?
Mineral is a naturally occuring inorganic solid with a definite chemical composition and physical structure. Common minerals include quartz, feldspar, mica , amphibole, olivine, and calcite. There are approximately 4000 different minerals, and each of those minerals has a unique set of physical properties.
What is the color of a mineral?
Color: The color of a mineral depends upon either the selective absorption of light or the reflection of light within the body of minerals. Color variation due to chemical impurities. E.g. Azurite –Blue, Malachite –Green, Pyrite –Yellow, Hematite –Gray.
What is luster in metal?
On the basis of variation in the nature of the reflecting surface, luster can be divided into the following categories: • Metallic luster: The shining surface to that of broken piece of metal. E.g. gold.
Mineral Hardness
The hardness of a mineral is defined by using the Mohs mineral hardness scale. Mineral hardness is the resistance or difficulty in scratching a mineral. Mohs mineral hardness scale has a ranking of 1 to 10 associated with 10 minerals to help determine the hardness of a mineral.
Mineral Luster
Mineral luster is a physical property that indicates how well light is reflected from a mineral. The common mineral luster categories are adamantine, dull, glassy, greasy, pearly, resinous, silky, vitreous and waxy.
The Physical Property of Color
Mineral color is quite possibly the best know physical property of a mineral available. Most people interested in minerals will focus on this physical property immediately, as finding the color of a mineral only requires the use of your eyes.
A Mineral Has Streak
Mineral streak is where you take a mineral and scratch it across a porcelain streak plate. When doing this, you produce a colorful mineral powder left behind on the porcelain surface. This colorful powder, or streak, is an important physical property of a mineral.
Specific Gravity of a Mineral
The specific gravity of a mineral requires measuring the mass of the mineral to the equal mass in volume of water. This measurement is a way to measure the density of minerals as minerals can have varying densities.
Mineral Cleavage
The physical property of mineral cleavage is the ability for a mineral to break smoothly along the minerals plane of weakness. This weakness is in the chemical bonding along a plane or multiple planes of the mineral.
Mineral Fracture
Mineral fracture much like mineral cleavage, is a break in the mineral. With a mineral facture the break is not just smooth, but can be conchoidal, sub-conchoidal, rough, fibrous, and uneven. A fracture break is a break that is not along one of the planes.
How are minerals identified?
Minerals are identified by analyzing their physical properties. Let’s learn about these properties and discover what they mean and how to determine them.
What is the hardness of a mineral?
Hardness. The hardness of a mineral is a way of describing how easy or difficult it is to scratch the mineral. It is used, in combination with the other physical properties, to help identify a mineral specimen.
1 Physical Properties of Minerals
The best way to practice observing and correctly identifying physical properties of minerals is by doing it in person. It is impossible to feel the relative weight of a mineral or the way it smells or tastes, for example. These exercises are meant as a selective review of some of the physical properties than can be observed.
Cleavage and Fracture
Match the type of cleavage to each mineral. Two minerals have no cleavage.
What are the physical properties of minerals?
The physical properties of minerals are related to their chemical composition and bonding. Some characteristics, such as a mineral’s hardness, are more useful for mineral identification. Color is readily observable and certainly obvious, but it is usually less reliable than other physical properties.
Why do minerals break apart?
Breaking a mineral breaks its chemical bonds. Since some bonds are weaker than other bonds, each type of mineral is likely to break where the bonds between the atoms are weaker. For that reason, minerals break apart in characteristic ways.
What is the name of the mineral that has no cleavage?
Some minerals, such as quartz , have no cleavage whatsoever. When a mineral with no cleavage is broken apart by a hammer, it fractures in all directions. Quartz is said to exhibit conchoidal fracture. Conchoidal fracture is the way a thick piece of glass breaks with concentric, curving ridges on the broken surfaces.
What does 2.5 mean in chemistry?
A hardness of 2.5 simply means that the mineral is harder than gypsum (Mohs hardness of 2) and softer than calcite (Mohs hardness of 3) . To compare the hardness of two minerals see which mineral scratches the surface of the other. Table 2. Mohs Hardness Scale.
What is luster in science?
Luster describes the reflection of light off a mineral’s surface. Mineralogists have special terms to describe luster. One simple way to classify luster is based on whether the mineral is metallic or non-metallic. Minerals that are opaque and shiny, such as pyrite, have a metallic luster.
What is a mineral that breaks into perfectly flat surfaces?
A mineral that naturally breaks into perfectly flat surfaces is exhibiting cleavage . Not all minerals have cleavage. A cleavage represents a direction of weakness in the crystal lattice. Cleavage surfaces can be distinguished by how they consistently reflect light, as if polished, smooth, and even.
Why is fracture not always the same?
Fracture is not always the same in the same mineral because fracture is not determined by the structure of the mineral.
Why do minerals have flat surfaces?
You have now seen that flat surfaces on a mineral can be the result of how that mineral grew (its crystal form or mineral habit), or because of how the mineral broke. One way to tell the difference when examining a sample is to see if the flat surface repeats where the sample is broken.
What happens when a mineral breaks?
When the mineral breaks, it will come apart along these zones of weakness. If the zones of weakness are aligned, then the mineral will break along a plane called a cleavage plane. If the mineral has perfect cleavage, the broken surface will be smooth and flat.
What is the cleavage of a mineral?
A mineral may have one or more cleavage planes (Figure 1.11). Planes that are parallel to each other are considered the same direction of cleavage, and only count as one. If there is only one direction of cleavage, it is called basal cleavage. Minerals with basal cleavage will break apart in flat sheets. Two directions of cleavage is termed prismatic, while three directions of cleavage at 90 o is referred to as cubic. If there are three directions of cleavage not at 90 o, the cleavage is rhombohedral. A mineral with four directions of cleavage has octahedral cleavage.
What is the term for mineral cleavage at 90 o?
Minerals with basal cleavage will break apart in flat sheets. Two directions of cleavage is termed prismatic, while three directions of cleavage at 90 o is referred to as cubic. If there are three directions of cleavage not at 90 o, the cleavage is rhombohedral.
How is hardness determined?
Hardness refers to the resistance of a mineral to being scratched, and is determined by the strength of the chemical bonds between atoms within a mineral. Hardness is assessed by trying to scratch the mineral with another substance. The material that ends up with a scratch in it is softer; the material that made the scratch is harder.
What is streaked mineral?
A mineral’s streak is the colour of the powder mark left behind when the mineral is rubbed on an unglazed piece of porcelain called a streak plate (Figure 1.5). Notice that the streak of pyrite in Figure 1.5 is dark grey, even though the pyrite is a dull gold colour.
What is crystal form?
Crystal Form & Mineral Habit. The geometric shape that a mineral naturally grows into is its crystal form. Crystal form reflects the orderly internal arrangement of atoms within the mineral. If minerals have space to grow when they are developing, they will display their crystal form (e.g., Figure 1.8).
