Minerals possess a number of physical properties that aid in their identification. These are listed below with a brief description:
Color--The color of the specimen as it appears to the naked eye under normal lighting conditions. Some minerals such as gold will only appear as one color, but due to impurities and Crystal Light distortion, many minerals can appear in multiple colors. Therefore, observable specimen color is the least effective property in identification.
Streak--The color of a mineral in powdered form. A streak test is performed by dragging a freshly cleaved mineral surface across an unglazed porcelain surface. If the mineral is less hard than the porcelain, it will leave a stripe of color (the mineral in a powdered state). This is the true color of a mineral specimen as it lessens the impurity impact and eliminates the light distortion from the crystal. Although a mineral may have multiple observable specimen colors, it will only have one streak color.
Luster--Refers to the absorption, reflection, or refraction of light by the surface of a mineral. Minerals possess various lusters that are somewhat self-explanatory such as dull, earthy, adamantine, metallic, glassy, metallic, silky, greasy, pearly, and resinous.
Fluorescence--Some minerals fluoresce in ultraviolet light, and some minerals specimens may appear to fluoresce due to fluorescent mineral impurities, or due to locality. This is not an extremely reliable indicator property but can be used in conjunction with other identification properties.
Chemical Composition--Minerals are chemicals, either elements or compounds found naturally in the Earth. Some minerals have a fixed chemical composition, and some minerals have a rigid set of chemical composition parameters that allow for the replacement of certain elements with other elements. Chemical properties can be tested with the use of a blowpipe, flame color, bead test, and laboratory solution tests.
Hardness--Minerals are identified roughly by their hardness based on the Mohs scale of mineral hardness, a list of ten minerals from #1 (softest) to #10 (hardest). All minerals will fall somewhere along the scale, based on their ability to scratch any mineral with a number lower than theirs and their inability to scratch any mineral with a number higher than theirs.
Mohs Scale of Mineral Hardness
Specific Gravity--Is the relative weight of a mineral as compared to the weight of an equal volume of water. The specific gravity is also referred to as density and is expressed normally as an average of a small range of densities.
Some Common Minerals and Their Specific Gravity
Crystal Form--A mineral's crystals form into one of six mineral crystal systems: cubic, tetragonal, hexagonal, orthorhombic, monoclinic, or triclinic. The crystal form reflects the structure of the molecules and formation environment of the mineral. Although sometimes difficult, identification of a mineral's crystal form is an invaluable aid to mineral identification along with the other mineral properties.
Optical Properties--Used mainly be scientists, X-rays are sent through thin slices of mineral, producing identifying patterns of light which measure their index of refraction which is distinct for each mineral.
Cleavage--The way some minerals split along planes which are related to their mineral structure, parallel to any crystal faces. Cleavage is measured in degrees of perfection from poor, to fair, good, perfect, and eminent, and are described by the number and direction of cleavage planes. Some minerals do not show cleavage, but fracture in a way other than along any cleavage plain.
Magnetism--Certain minerals exhibit magnetism or an attraction to a magnet, and some will display this property only when heated.
Electrical Properties--Some minerals when heated or rubbed will develop an electrical charge. Others will be able to control radio frequencies.
Melting Point--A pure mineral will posses a melting point which can be tested with a high temperature flame until it fuses at the edges.
Some minerals can be identified by their unique characteristics. Sulfur can be identified by its smell, while halite (salt), by its taste.
Some notable mineralogists include Johann Wolfgang von Goethe, who made contributions to mineralogy while also being a writer and statesman, and James Dwight Dana, who is known for his work on crystal structures and mineral classification. William Hallowes Miller developed the Miller indices system for crystallography and is considered a pioneer in the field of crystallography.
A scientist conducts research and experiments to expand knowledge in a particular field. Zoologists study animals and their behavior, while botanists focus on plants. Geologists study the Earth's structure and processes, while mineralogists specialize in minerals and their properties.
Rocks and minerals are identified differently because they have distinct characteristics. Minerals are naturally occurring, inorganic solids with a specific chemical composition and crystal structure, whereas rocks are composed of one or more minerals or mineraloids and can also include organic materials. Identification of minerals focuses on their physical and chemical properties, such as hardness and cleavage, while rock identification involves examining the composition, texture, and formation processes of the rock as a whole. This differentiation reflects their unique roles in geology and earth sciences.
Minerals have a well-defined crystalline structure, whereas natural glasses do not have a crystalline structure and are amorphous. Additionally, minerals have a specific chemical composition, while natural glasses can have variable compositions.
No, not all minerals are inorganic. While most minerals are classified as inorganic, there are exceptions, such as certain organic minerals like some carbonates and sulfates that can contain organic compounds. Additionally, minerals can form from biological processes, such as the formation of shells and skeletons in marine organisms. Thus, while the majority of minerals are inorganic, there are organic minerals that exist as well.
The color left on a streak plate when the mineral is scratched on the surface of the plate. Different minerals have different streak colors. The mineral is tested for hardness to see where it lies on the Mohs scale. The crystal structure (othorhombic, tetragonal, triclinic, isometric, monoclinic, or trigonal), will help identify the mineral. Different minerals have different densities and weights.
The color left on a streak plate when the mineral is scratched on the surface of the plate. Different minerals have different streak colors. The mineral is tested for hardness to see where it lies on the Mohs scale. The crystal structure (othorhombic, tetragonal, triclinic, isometric, monoclinic, or trigonal), will help identify the mineral. Different minerals have different densities and weights.
The color left on a streak plate when the mineral is scratched on the surface of the plate. Different minerals have different streak colors. The mineral is tested for hardness to see where it lies on the Mohs scale. The crystal structure (othorhombic, tetragonal, triclinic, isometric, monoclinic, or trigonal), will help identify the mineral. Different minerals have different densities and weights.
Mineralogists use their senses to gather information about the physical properties of minerals such as color, texture, luster, hardness, and crystal form. These observations help identify minerals and determine their chemical composition, which can provide important clues about their formation and geological context.
they use their senses because they are supposed to see the Mohs scale of the rocks. They test it out, they put stuff like oil on them, and they smell, touch what it feels like and they hear the noise of the rock by banging it and when their done they write their feelings on an expiriment paper. Thank you :)
Some notable mineralogists include Johann Wolfgang von Goethe, who made contributions to mineralogy while also being a writer and statesman, and James Dwight Dana, who is known for his work on crystal structures and mineral classification. William Hallowes Miller developed the Miller indices system for crystallography and is considered a pioneer in the field of crystallography.
A scientist conducts research and experiments to expand knowledge in a particular field. Zoologists study animals and their behavior, while botanists focus on plants. Geologists study the Earth's structure and processes, while mineralogists specialize in minerals and their properties.
Rocks and minerals are identified differently because they have distinct characteristics. Minerals are naturally occurring, inorganic solids with a specific chemical composition and crystal structure, whereas rocks are composed of one or more minerals or mineraloids and can also include organic materials. Identification of minerals focuses on their physical and chemical properties, such as hardness and cleavage, while rock identification involves examining the composition, texture, and formation processes of the rock as a whole. This differentiation reflects their unique roles in geology and earth sciences.
Minerals have a well-defined crystalline structure, whereas natural glasses do not have a crystalline structure and are amorphous. Additionally, minerals have a specific chemical composition, while natural glasses can have variable compositions.
The study of rocks is known as petrology, while the study of soil is known as pedology. Both fields involve examining the composition, formation, and characteristics of rocks and soil, respectively.
When minerals are hit with a hammer, they may break, fracture, or shatter, depending on their hardness and crystal structure. Some minerals will form cleavage along specific planes, while others will show irregular fractures. This property can be used to help identify minerals based on their physical characteristics.
Stones are small, solid pieces of minerals or rocks, while rocks are larger and made up of one or more minerals. Stones are typically smooth and rounded, while rocks can have various shapes and textures. In terms of geological characteristics, rocks are classified based on their formation process and composition, while stones are generally considered to be smaller fragments of rocks.