Sphalerite cleavage. Practical tips on Sphalerite Facet / Faceting Informati...

Sphalerite can be difficult to identify because of its var

Sphalerite (which is also known as Blende), is an important ore of zinc and can make a rather attractive cabinet specimen as well. It can have excellent luster and associates with many beautifully colored minerals making it one of the best enhancers of many fine mineral specimens. ... Cleavage is perfect in six directions forming dodecahedrons ...note: Specific Gravity of Sphalerite =4.08 gm/cc. Fermion Index: Fermion Index = 0.02 Boson Index = 0.98 : Photoelectric: PE Sphalerite = 35.10 barns/electron U=PE Sphalerite x rElectron Density= 135.25 barns/cc. Radioactivity: GRapi = 0 (Gamma Ray American Petroleum Institute Units) Sphalerite is Not Radioactive : Sphalerite Classification ... Sphalerite crystallizes in the isometric crystal system and possesses perfect dodecahedral cleavage. In the crystal structure, zinc and sulfur atoms are tetrahedrally …Sphalerite has 6 directions of cleavage, and has a pale yellow streak. Fluorite has 4 cleavage directions. E. Fracture: Olivine and quartz have a smooth curved (concoidal) fracture. Most of the others have an uneven fracture (e.g., garnet, magnetite, corundum, pyrite, hematite). ...Zinc sulfide (ZnS) is a unique compound that forms two types of crystalline structures. These two polymorphs are wurtzite and zincblende (also known as sphalerite). Wurtzite has a hexagonal structure, while zincblende is cubic. It is characterized by single bonds between each atom and maintenance of a 1:1 zinc to sulfur ratio.Sphalerite. Type: Mineral: Luster: Nonmetallic Resinous: Hardness: 3.5 - 4 > Fingernail but < Glass: Cleavage: Yes 6 perfect cleavages: Streak: Pale Yellow: Color: Yellow Brown to Black: Miscellaneous: Powdered streak smells like rotten egg: East Carolina University Department of Geological SciencesSome calcite specimens contain euhedral crystals, but many are rhombohedral cleavage fragments like those in Figures 14.361 and 14.362. The photo in Figure 14.361 shows calcite with its most common whitish color. The photo in Figure 14.362 shows (less common) blue calcite cleavage fragments. Other colors too, are possible.Cleavage may be visible / Twinning rare and difficult to see / Lamellar exsolution / Replacement textures with Chalcopyrite Enargite Digenite common / Alters on grain boundaries and fractures to Covellite: Chalcopyrite Covellite Digenite Enargite Galena Hematite Linnaeite Magnetite Pyrite Sphalerite Tetrahedrite: None: Low 2-22%: Extra …Sphalerite can be difficult to identify because of its variable luster, color, abundant but obscured cleavage and crystal habits. So difficult was sphalerite for miners to distinguish from more valuable minerals such as galena, acanthite and tetrahedrite, that they named it sphalerite which is Greek for treacherous rock and blende is German for ... Cleavage may be visible / Twinning rare and difficult to see / Lamellar exsolution / Replacement textures with Chalcopyrite Enargite Digenite common / Alters on grain boundaries and fractures to Covellite: Chalcopyrite Covellite Digenite Enargite Galena Hematite Linnaeite Magnetite Pyrite Sphalerite Tetrahedrite: None: Low 2-22%: Extra Soft (87 ...Although sphalerite (SFAL-er-ite) has a hardness of only 3 1/2 to 4 and possesses six directions of perfect dodecahedral cleavage, transparent stones are highly prized by collectors because of the mineral's tremendous dispersion (0.156) and R.I. (about 2.37). The resultant brilliancy and fire displayed by green, greenish-brown, yellow-brown or ...Sphalerite. Sphalerite is an ore—a mineral of economic value—that was once mined in southeastern Kansas for its zinc content. It is also called zinc blende, blende, blackjack, and mock lead. Sphalerite crystals are usually shaped like triangular pyramids, with three sides and a base. Because it has good cleavage in six directions ...1. Sphalerite - color resinous yellow to dark brown; cleavage perfect in six directions; soft. 2. Amphibole - color dark green to black; cleavage in two directions. 3. Biotite - color brown to black; cleavage perfect in one direction (cleaves into flexible, elastic sheets). 4. Feldspar - color variable, occasionally dark grey; cleavage excellent in SPHALERITE - ZnS Sphalerite (old names: “blende ”, “zinc blende”) is a common sulfide and the main ore of Zn. May constitute a Cd ore. Sphalerite is usually massive. Crystals are rare, tetrahedral and dodecahedral, typically very complex and distorted (conical and curved faces); can look like octahedrons, reach 30 cm. Twins are common, Physical Properties of Millerite : Cleavage: {1011} Perfect, {0112} Perfect : Color: Bronze, Greenish gray, Gray, Brass yellow. Density: 5.5Sphalerite, for the same reason, is derived from a Greek word meaning treacherous. Sphalerite is the most important ore of zinc. The chief uses for metallic zinc are in galvanizing iron, making brass, (an alloy of copper and zinc), in electric batteries, and as sheet zinc. Dolomite is a common rock-forming mineral. It is a calcium magnesium carbonate with a chemical composition of CaMg (CO 3) 2. It is the primary component of the sedimentary rock known as dolostone and the metamorphic rock known as dolomitic marble. Limestone that contains some dolomite is known as dolomitic limestone.Figure \(\PageIndex{1}\): Round Brilliant Sphalerite Photo courtesy of Rick Martin, Art Cut GemsPlagioclase feldspar. Mineral Type: Cleavage. A nonmetallic mineral that is grey, grey-green, white, or blue in color, has 2 perfect cleavage planes at 90° with one plane showing striations (a growth pattern that appears as thin grooves), and a hardness of 6.0.Three cleavage directions: if they intersect at 90˚ = cubic cleavage; if the angles are not 90˚ = rhombohedral. Minerals with 4 or 6 cleavages are not common. Four cleavage planes can form an 8-sided shape = octahedral cleavage (e.g., fluorite). Six cleavage planes can form a 12-sided shape = dodecahedral cleavage (e.g., sphalerite).cleavage planes. xO.8. FIGURE 1.13. Six directions of cleavage (dodecahedral cleavage) in a sample of sphalerite. A. Irregular fracture x 1. B. Conchoidal ...Cleavage. Yes. 6 perfect cleavages. Streak. Pale Yellow. Color. Yellow Brown to Black. Miscellaneous. Powdered streak smells like rotten egg.Sphalerite. Type: Mineral: Luster: Nonmetallic Resinous: Hardness: 3.5 - 4 > Fingernail but < Glass: Cleavage: Yes 6 perfect cleavages: Streak: Pale Yellow: Color: Yellow Brown to Black: Miscellaneous: Powdered streak smells like rotten egg: East Carolina University Department of Geological SciencesSphalerite has perfect cleavage, but if the crystals are very small you may not be able to note this. This is the most important ore mineral of zinc. It's ...Submetallic luster on sphalerite: Has the appearance of dull metal, like pewter. These minerals would usually still be considered metallic. ... Cleavage planes arise from the tendency of mineral crystals to break along specific planes of weakness within the crystal favored by atomic arrangements. The number of cleavage planes, the quality of ...Magnetite is a black, opaque, magnetic mineral that leaves a black streak when rubbed across a hard rough surface. It is one of the most abundant metal oxides, and its crystal structure contains both the ferrous (Fe+2) and ferric (Fe+3) forms of iron ions. A complex pattern of electrons between the two forms of iron is the source of its ...1.. IntroductionNaturally occurring Fe-containing sphalerite Zn x Fe 1−x S is the world’s primary source of Zn. A knowledge of the surface composition and structure for a number of metal sulfides is of critical importance in the control of mineral surface reactivity, for mineral separation by flotation and in sulfide mineral leaching for metal recovery or control of environmental pollution ...Sphalerite is the principle ore of zinc. In some localities, it occurs with significant amounts of the rare element s cadmium, gallium, and iridium, and it is also the main ore of those metal s. Sphalerite is an important mineral to collectors, and some transparent varieties are occasionally faceted for collectors. NOTEWORTHY LOCALITIES. Define sphalerite. sphalerite synonyms, sphalerite pronunciation, sphalerite translation, English dictionary definition of sphalerite. n. The primary ore of zinc, occurring in usually yellow-brown or brownish-black crystals or cleavage masses, essentially ZnS with some cadmium, iron, and...One occurs abundantly as massive material, and has the physical properties of iron- bearing sphalerite. Carefully selected cleavage fragments give r-ray powder ...8 Kas 2018 ... Crystal Structure of Sphalerite. The sphalerite chemical formula is ZnS (zinc sulfide.) This chemical formula represents sphalerite in its pure ...Gemological Institute of America 12 [view label] Owner: RRUFF Description: Light yellow-green cleavage fragment ... sphalerite, American Mineralogist, 106, 196- ...Pyrite is a pretty mineral (Fig&period; 1) common to Indiana, but it also has a dark side. It is composed of iron (Fe) and Sulfur (S) with a chemical formula of FeS2. Atoms are arranged in an isometric crystal structure (Fig&period; 2) that makes cubic crystals. It shows a brassy, bright metallic luster when fresh, but readily tarnishes to dull surfaces upon exposure …5 Flourite; 8 Obsidian; 8 Serpentine; 5 Sphalerite; 5 Biotite mica; 5 Calcite; 5 Halite; 5 Hornblend; 5 Microline feldspar ...Mineral Name: Chalcopyrite. Chemical Composition: (CuFeS2) Copper Iron Sulfide. Color: Brass-yellow, dull gray-green, acid treated tarnish red-blue-purple iridescence. Streak: Chalcopyrite has a greenish gray/black streak. Hardness: 3.5-4 on the Moh’s hardness scale. Cleavage/Fracture: Chalcopyrite has poor cleavage, which means it does not ...Sphalerite is zinc sulfide, an ore of zinc. The name comes from the Greek "sphaleros," meaning treacherous, in reference to how easy it is to mistake the darker varieties for galena, a lead ore. ... (3.5-4.0 Mohs scale) and perfect cleavage, sphalerite is a fragile gemstone that is not commonly used in jewelry. However, it shows great ...Sphalerite has 6 directions of cleavage, and has a pale yellow streak. Fluorite has 4 cleavage directions. E. Fracture: Olivine and quartz have a smooth curved (concoidal) fracture. Most of the others have an uneven fracture (e.g., garnet, magnetite, corundum, pyrite, hematite). ...Sphalerite is zinc sulfide, an ore of zinc. The name comes from the Greek "sphaleros," meaning treacherous, in reference to how easy it is to mistake the darker varieties for galena, a lead ore. ... (3.5-4.0 Mohs scale) and perfect cleavage, sphalerite is a fragile gemstone that is not commonly used in jewelry. However, it shows great ...Cleavage may be visible / Twinning rare and difficult to see / Lamellar exsolution / Replacement textures with Chalcopyrite Enargite Digenite common / Alters on grain boundaries and fractures to Covellite: Chalcopyrite Covellite Digenite Enargite Galena Hematite Linnaeite Magnetite Pyrite Sphalerite Tetrahedrite: None: Low 2-22%: Extra …Sphalerite cleavage surface dissolution in acidic (HC1) and oxygen-saturated solutions was investigated by liquid-cell Atomic Force Microscopy (AFM). The sphalerite surface was cleaved in the laboratory and then mounted in the liquid cell at 298 K with a fast continuous renewal of the interacting solution. AFM data indicate that unreacted (110 ...Aug 28, 2022 · It is a dense mineral with perfect cleavage but comes in many colors. It is most easily recognized when it has a brown to yellow resinous to adamantine luster (Figure 14.247). But sphalerite may be black, it may have a metallic luster (Figure 14.248), and it may occur as light brown or yellow clear to translucent crystals (Figure 14.249). Sphalerite (Zn,Fe)S c 2001-2005 Mineral Data Publishing, version 1 Crystal Data: Cubic. Point Group: 43m. Crystals tetrahedral, dodecahedral, typically complex and distorted, curved and conical faces common, to 30 cm. Also fibrous, botryoidal, stalactitic, cleavable, coarse to fine granular, massive. Twinning: Twin axis [111], twin plane You can understand the properties of a silicate mineral such as crystal shape and cleavage by knowing which type of crystal lattice it has. In nesosilicates ...Sphalerite (Zn,Fe)S c 2001-2005 Mineral Data Publishing, version 1 Crystal Data: Cubic. Point Group: 43m. Crystals tetrahedral, dodecahedral, typically complex and distorted, curved and conical faces common, to 30 cm. Also fibrous, botryoidal, stalactitic, cleavable, coarse to fine granular, massive. Twinning: Twin axis [111], twin planeSulfides are well known for being important ore minerals. For example, galena is the main source of lead, sphalerite is the main source of zinc, and chalcopyrite is the main copper ore mineral mined in porphyry deposits like the Bingham mine (see chapter 16). The largest sources of nickel, antimony, molybdenum, arsenic, and mercury are also ...Sphalerite makes an excellent collector’s stone, but it is too soft for jewelry. It is difficult to cut and polish due to perfect cleavage in six directions. Gemstone-quality material, when faceted, is remarkable due to its incredibly high dispersion. Uses of Arsenopyrite and Arsenic. Arsenopyrite is the primary ore of arsenic metal. The mineral contains approximately 46% arsenic by weight. Arsenic metal is used to produce a variety of alloys. It was historically used to harden lead in ammunition, but this use was nearly eliminated by the late 1900s.One of the most distinctive properties of sphalerite is its cleavage. It has six directions of perfect cleavage with faces that exhibit a resinous to adamantine luster. Specimens that display this distinctive cleavage are easy to identify. Unfortunately, many specimens …We would like to show you a description here but the site won’t allow us.Sphalerite is one of the very few minerals that has a total of six directions of cleavage. If all of them were to be perfectly cleaved on a single crystal it would form a rhombic …sphalerite. sulfides. Its name comes from the Greek “sphaleros” meaning traitor ... easy cleavage in three directions. OPTICAL PROPERTIES. Transparency.General Talc Information : Chemical Formula: Mg3Si4O10(OH)2 : Composition: Molecular Weight = 379.27 gm Magnesium 19.23 % Mg 31.88 % MgO: Silicon 29.62 % Si 63.37 % SiO 2Sphalerite is one of the very few minerals that has a total of six directions of cleavage. If all of them were to be perfectly cleaved on a single crystal it would form a rhombic …Minerals that have cleavage can also fracture along surfaces that are not parallel to their cleavage planes (Figure 2.3.6). Figure 2.3.5: Common types of cleavage, and conchoidal fracture (top left), with illustrations to indicate cleavage directions and angles between cleavage planes. Figure 2.3.6: Cleavage and fracture in potassium feldspar.Minerals that have cleavage can also fracture along surfaces that are not parallel to their cleavage planes (Figure 2.3.6). Figure 2.3.5: Common types of cleavage, and conchoidal fracture (top left), with illustrations to indicate cleavage directions and angles between cleavage planes. Figure 2.3.6: Cleavage and fracture in potassium feldspar.Sphalerite (cont) Sphalerite (cont) Chemical compos‐ ition (Zn,fe)s Hornblende Hornblende Form Prismatic, Tabular Colour Black, Dark green Lustre Vitreous Streak Colourless Hardness 5- Cleavage Imperfect Fracture Uneven Sp. Gravity 2-3. Microcline Microcline Form Prismatic, granular Colour White, gray Luster Vitreous Streak …Black Jack. Blende. Zinc Blende. VARIETIES. Cleiophane. - Transparent, lightly colored variety of Sphalerite. Marmatite. - Opaque, metallic luster ed, ironrich variety of …Mineral Name: Chalcopyrite. Chemical Composition: (CuFeS2) Copper Iron Sulfide. Color: Brass-yellow, dull gray-green, acid treated tarnish red-blue-purple iridescence. Streak: Chalcopyrite has a greenish gray/black streak. Hardness: 3.5-4 on the Moh’s hardness scale. Cleavage/Fracture: Chalcopyrite has poor cleavage, which means it does not ...Cleavage: complete. Crystal: isometric (tetrahedral, dodecahedral) sometimes granular. Envronment: mesothermal veins, limestones, hydrothermal deposits.SILICATES. Based on the polyatomic anion, (SiO 4) 4–, which has a tetrahedral shape.Most minerals in the earth’s crust and mantle are silicate minerals. All silicate minerals are built of silicon-oxygen tetrahedra (SiO 4) 4– in different bonding arrangements which create different crystal lattices. You can understand the properties of a silicate mineral such as crystal …The simulations of O2 and CN adsorption on copper activated sphalerite (110) surface are performed by using plane wave-pseudopotential approach based on density functional theory.Study Test one Identification(Lab) flashcards. Create flashcards for FREE and quiz yourself with an interactive flipper.Cleavage: {110} Distinct : Color: Tin white, Light steel gray. Density: 6.07 : Diaphaneity: Opaque : Fracture: Brittle - Generally displayed by glasses and most non-metallic minerals. Habit: Euhedral Crystals - Occurs as well-formed crystals showing good external form. Habit: Prismatic - Crystals Shaped like Slender Prisms (e.g. tourmaline). Habit:Sphalerite can be difficult to identify because of its variable luster, color, abundant but obscured cleavage and crystal habits. So difficult was sphalerite for miners to distinguish from more valuable minerals such as galena, acanthite and tetrahedrite, that they named it sphalerite which is Greek for treacherous rock and blende is German for ...Sphalerite has dodecahedral cleavage. Intentionally, the description above was constrained to 3D crystals which eventually are (typically) described in one of 230 3D space groups. Note, there equally are seven planar space groups , and a growing body of work about 2D crystals , too.Orienting along the 3-fold axis leaves us with 6 cleavage planes on the girdle. Not good, but if you orient the girdle facets at skew to the cleavages, its ...SPHALERITE - ZnS Sphalerite (old names: “blende ”, “zinc blende”) is a common sulfide and the main ore of Zn. May constitute a Cd ore. Sphalerite is usually massive. Crystals are rare, tetrahedral and dodecahedral, typically very complex and distorted (conical and curved faces); can look like octahedrons, reach 30 cm. Twins are common, All members of the calcite group crystallize in the trigonal system, and have perfect rhombohedral cleavage. Siderite is easily altered to iron oxides. A brown Goethite replacement of Siderite is common. Limonite, an amorphous mineral, is commonly found in rhombohedral crystals, as it frequently pseudomorphs after Siderite.Cleavage/Fracture: Cleavage is dodecahedral in 6 directions of perfect cleavage, and fracture is conchoidal meaning it resembles the shape of a scallop shell. (3, 1) Crystal Form: Most commonly, sphalerite is found shaped as tetrahedral crystals, with a pyramid-type shape. The crystal faces are usually somewhat rounded or curved.General Talc Information : Chemical Formula: Mg3Si4O10(OH)2 : Composition: Molecular Weight = 379.27 gm Magnesium 19.23 % Mg 31.88 % MgO: Silicon 29.62 % Si 63.37 % SiO 2Type Mineral Luster Nonmetallic Resinous Hardness 3.5 – 4 > Fingernail but < Glass Cleavage Yes 6 perfect cleavages Streak Pale Yellow Color Yellow Brown to Black Miscellaneous Powdered streak smells like rotten egg Sphalerite 2.5 Gray 3 cleavage planes at 90° Silvery gray, very high specific gravity Metallic Galena 1 to 2 Gray to black Poorly defined cleavage in one direction Dark gray to black, marks paper Metallic to dull or greasy Graphite 7 No streak Conchoidal or irregular fracture Colorless, white, or other colors, transparent to translucentColor: Silvery yellow-brown, silvery red, black with sub metallic to resinous luster. Streak: White --> pale yellow brown. Hardness: H 5-6 (Soft/Hard) Cleavage/Fracture: Good --> excellent cleavage. Special Properties: Smells like rotten eggs when scratched, powdered or in acid test (HCl) Galena (90 degree edges) Luster: Metallic.Sphalerite. Sphalerite is an ore—a mineral of economic value—that was once mined in southeastern Kansas for its zinc content. It is also called zinc blende, blende, blackjack, and mock lead. Sphalerite crystals are usually shaped like triangular pyramids, with three sides and a base. Because it has good cleavage in six directions ... Dodecahedral cleavage: some high symmetry minerals may have six cleavage planes that intersect in space separating small dodecahedrons (e.g. sphalerite). Pinacoidal cleavage : it occurs in some prismatic minerals like barite, whose planes of weakness are oblique to both the basal and prismatic planes (i.e. pinacoidal plane).Pyrrhotite. Comments: Lustrous sharp crystals of pyrrhotite to 3.5 cm in size with minor sphalerite and chalcopyrite. Location: Nikolaevskiy mine, Dal'negors, Primorskiy Kray, Russia. Sphalerite - Just like other minerals, it was first gathered Sphalerite - Sphalerite contains Zinc, where it was used and concentrated. Next, the mineral is roasted to be as construction materials. reduced to powder. It is then neutralized and the contaminants are removed by filtration. The Zinc thenOct 7, 2020 · Sphalerite. Chemical composition: ZnS. Color and Luster: color varies from yellow to light to dark brown, red-brown, red, black, and colorless, and is less commonly light blue or green. It has a resinous to adamantine luster. Hardness: 3.5 to 4. Cleavage: 1 perfect. Specific gravity: 3.9 to 4.1. Crystal system: Isometric crystal system List the 2 most common rock-forming mineral groups. Write a statement that describes the movement of water through the hydrologic cycle, citing several of the processes that are involved. Movement from water from the oceans to the atmosphere, to the land & sea. Evaporation, precipitation, runoff, and infiltration.Because of its low hardness (3.5-4.0 Mohs scale) and perfect cleavage, sphalerite is a fragile gemstone that is not commonly used in jewelry. However, it shows great dispersion, three times that of diamond, making it a popular collector’s gem. This 214.21ct sphalerite from Spain has a deep brownish-orange color with pronounced dispersion. Sphalerite Meanings, Zodiacs, Planets, Elements, Colors, Chakras, and more. Science & Origin of SphaleriteSphalerite, also known as zinc blende and black-jack, is a zinc sulfide mineral that crystallizes in the form of masses, botryoidal, cubes, tetrahedral crystals, and dodecahedral crystals. Its most commonly silver and grey, but can also be seen as red, black, yellow, brown, green, and ... Properties in Thin Section Sphalerite is colorless to pale brown or yellow in thin section. It has extremely high relief and good cleavage. Isotropic, n = 2.42. Crystallography Sphalerite is a cubic mineral, a = 5.785, Z = 4. space group \(F\overline{4}3m\); point group \(\overline{4}3m\).. Habit Sphalerite crystals may be distorted or rounded. Crystals show combinations of tetrahedra ...It has a Mohs hardness of 3.5-4.0, a subconchoidal fracture, perfect cleavage in six directions, a resinous-to-greasy luster, and a specific gravity of 3.9-4.1. Sphalerite is occasionally transparent, but is usually translucent to opaque with colors ranging from yellow and yellow-brown to reddish-brown, green, and near-black.I'd say it's impressive on both ends. The faces on the gem are its planes of cleavage, which are where the chemical structure is most likely to fracture. The cut it certainly impressive, but it was aided by sphalerite's chemical properties. Scroll down to the crystallographic forms for a 3D image. Edit: It looks like I was a bit off about cleavage.Sphalerite 2.5 Gray 3 cleavage planes at 90° Silvery gray, very high specific gravity Metallic Galena 1 to 2 Gray to black Poorly defined cleavage in one direction Dark gray to black, marks paper Metallic to dull or greasy Graphite 7 No streak Conchoidal or irregular fracture Colorless, white, or other colors, transparent to translucentCalcite has perfect cleavage in three directions to produce rhombohedra. (Cleavage in aragonite is generally less well developed.) Hardness. 3 (down to 2.5 on some surfaces) – easily scratched by a metal nail, but too hard to be scratched by a fingernail. Aragonite is slightly harder, from 3.5 to 4. Specific Gravity. Sphalerite (sometimes spelled sphaelerite) (which is also known as Blende), is an important ore of zinc and can make a rather attractive cabinet specimen as ...Physical properties. Sphalerite possesses perfect dodecahedral cleavage, having six cleavage planes. [10] [18] In pure form, it is a semiconductor, but transitions to a …Gemological Institute of America 12 [view label] Owner: RRUFF Description: Light yellow-green cleavage fragment ... sphalerite, American Mineralogist, 106, 196- .... Description and Identifying Characteristics Its perfect cub... sphalerite (as measured via sodium light, 589.3 n The cleavage behavior of the crystal is governed by the breaking of chemical bonds bridging the cleavage surface. For zinc-blende crystals this depends on ...The other specimen 8c is also quartz It is described as crystalline and consists from GEOL 1403 at Blinn College Black Jack. Blende. Zinc Blende. VARIETIES. Hardness greater than glass (H ~ 6-6.5); Brassy yellow color; black streak; Crystals commonly cubic; no cleavage. Galena: Metallic: Softer than glass: 3 perfect cleavages at 90 degrees, high density. Hematite: Metallic or non-metallic luster: Hard to tell, but harder: Red-brown streak. Hornblende: Non-metallic (black) Harder than glass With dispersion of around four times that of diamond, ...

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