Sphalerite hardness

Sphalerite is a common mineral, and occurs in many distinct colors and forms. Iron impurities are often present in this mineral, and for this reason it is not commonly transparent. If Sphalerite contains a large amount of iron impurities, it will have a metallic dark gray or black color, which is typical of most sulfide minerals. Sphalerite is one of the few minerals that can range from gemmy ...

Sphalerite hardness. Sphalerite is a sulfide mineral with the chemical formula S. It is the most important ore of zinc. Sphalerite is found in a variety of deposit types, but it is primarily in sedimentary exhalative, Mississippi-Valley type, and volcanogenic massive sulfide deposits. It is found in association with galena, chalcopyrite, pyrite , calcite, dolomite, quartz, rhodochrosite, and fluorite.

Pure sphalerite has a white streak. However, impurities are almost always present, giving this mineral a light brown streak. ... A standard hardness scale, called Mohs Scale of Hardness, is named after the scientist Friedrich Mohs (1773-1839). It is a relational scale that ranges from 1 for the least hard minerals to 10 for the hardest mineral ...

Mineral Identification Key - Table IB. The Mineral Identification Key. Table IB: Minerals with Metallic or Submetallic Luster & Hardness greater than 2½, but less than 5½: (Will not easily mark paper, but can be scratched with a pocket knife.) [ Previous Table ] [ Next Table ] Hardness. Color.Physical properties Sphalerite possesses perfect dodecahedral cleavage, having six cleavage planes. [10] [18] In pure form, it is a semiconductor, but transitions to a conductor as the iron content increases. [19] It has a hardness of 3.5 to 4 on the Mohs scale of mineral hardness. [20] Pure sphalerite has a white streak. However, impurities are almost always present, giving this mineral a light brown streak. ... A standard hardness scale, called Mohs Scale of Hardness, is named after the scientist Friedrich Mohs (1773-1839). It is a relational scale that ranges from 1 for the least hard minerals to 10 for the hardest mineral ...Physical properties Sphalerite possesses perfect dodecahedral cleavage, having six cleavage planes. [10] [18] In pure form, it is a semiconductor, but transitions to a conductor as the iron content increases. [19] It has a hardness of 3.5 to 4 on the Mohs scale of mineral hardness. [20]The hardness varies between 5.5 and 6.0 in Mohs scale. Figure 1.31. Arsenopyrite is a hard metallic iron arsenic sulfide with steel gray to silver-white color, and the major source of arsenic. ... galena, and sphalerite. Oxidation of arsenopyrite led to the formation of scorodite on the surface.Sphalerite possesses perfect dodecahedral cleavage, having six cleavage planes. In pure form, it is a semiconductor, but transitions to a conductor as the iron content increases. It has a hardness of 3.5 to 4 on the Mohs scale of mineral hardness.sphalerite (ZnS) and pyrite (FeS2) to be exploited in flotation and/or magnetic separation by using microwave energy because these minerals are the main constituents of the complex ore deposits all over the world. Material and experimental study Sphalerite, galena and pyrite samples used in the experimentsTwo minerals of note have differences in hardness depending on direction: Kyanite has a hardness of 5 parallel to the length of the crystal, and a hardness of 7 when scratched along a direction perpendicular to the length. Calcite has a hardness of 3 for all surfaces except the {0001} plane. On {0001} it has a hardness of 2.

Cooking hard boiled eggs can be a tricky task. If you don’t get the timing just right, you can end up with an egg that is either undercooked or overcooked. But even if you do get the cooking time perfect, peeling the egg can be a challenge....Study with Quizlet and memorize flashcards containing terms like Hematite, Magnetite, Sphalerite and more. Study with Quizlet and memorize flashcards containing terms like Hematite, Magnetite, Sphalerite and more. Home. Subjects. Expert solutions. Create ... hardness:3.5-4 Streak: light yellow-brown[1] The name sphalerite is from the Greek word "sphaleros" which means deceiving or treacherous. This name is in response to the many different appearances of sphalerite and because it can be challenging to identify in hand specimens. Sphalerite is a sulfide mineral with the chemical formula S. It is the most important ore of zinc. Sphalerite is found in a variety of deposit types, but it is primarily in sedimentary …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 systemSphalerite; Chemical composition (Zn,Fe)S: Crystal system: Cubic: Habit: Tetrahedral or dodecahedral: Cleavage: Perfect in 6 directions; easily developed: Fracture: Concoidal to uneven: Hardness: 3.5-4.0: Optic nature: Isotropic: Refractive index: 2.368 - 2.50 (increases with Fe content) Specific gravity: 3.95-4.10: Lustre: Adamantine to ...

Name: sphalerite (blende) ; Class: Sulfides ; Chemistry: ZnS Zinc Sulfide ; Color(s):. yellow, yellow-brown, brown to black, seldom red or green ; Hardness: 3.5 - ...Description: Sphalerite is the most common and important zinc mineral. Sphalerite has a beautiful shine, but is very soft, and it’s color varies. Sphalerite is non-metallic. Uses: Galvanized iron, batteries, brass. Used in mildew resistant element in some paint. Sphalerite is used in dyes, medicine, and more.Now, the mineral Sphalerite has a hardenss of about 3.5-4. Meaning, depending on how hard it really ends up being, it will be on the lower end of the hardness scale. it would be able to be scratched by anything over the 3.5 hardness. Including a copper coin. It would be between the hardness of Calcite and Fluorite.This Sphalerite gemstone guide lists qualities of the Sphalerite gem type, including stone colors, common names, meanings, gemstone hardness and more. Calcite 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.

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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 ...Sphalerite is a zinc ore mineral that typically contains iron. When it has a high iron content, sphalerite is an opaque black. Gem-quality material has a low iron content, resulting in transparent crystals. Due to its lack of hardness, it is mainly a collector's gemstone. One of the most notable characteristics of sphalerite is its high ...According to Encyclopedia Britannica, hard news is the coverage of issues such as politics, economics, international relations, welfare and scientific developments. Hard news can be delivered that is of local, regional, national or internat...[1] The name sphalerite is from the Greek word "sphaleros" which means deceiving or treacherous. This name is in response to the many different appearances of sphalerite and because it can be challenging to identify in hand specimens.Sep 1, 2020 · Sphalerite is common in lithologies consisting of stratabound fine-grained pyrite where it exhibits infill and replacement textures (Fig. 6 a–c). While sphalerite is still regularly abundant, galena is primarily localised to carbonate-rich layers, discordant silica-dolomite, and in deformed carbonaceous shale (Fig. 6 d–e). On a macroscopic ...

Sphalerite is also referred to as Blende or Zinc Blende, and is the major ore of zinc. ... The density of sphalerite is 3.9-4.2 g/cm 3 and hardness is 3.5 - 4 – between copper penny and fluorite. Global Distribution. Sphalerite is widely distributed, and good examples can be found in the following locations: England - From Alston Moor, Cumbria;With a hardness of just 3.5 to 4, sphalerite can be scratched very easily. Common household dust, with a hardness of 7, would scratch sphalerite if you wiped it off with a cloth. Faceters also face additional challenges cutting this stone. It has six perfect cleavage planes in its isometric crystal structure and it’s brittle. C) hardness and streak D) streak and cleavage 40.Which two properties are most useful in distinguishing between galena and halite? A) shale B) phyllite C)dunite D) schist 41.A nonvesicular rock is made entirely of green 2-millimeter-diameter crystals that have a hardness of 6.5 and show fracture, but notcleavage. The rock is most likely A ...Hardness = 3.5-4 VHN = 208-224 (100 g load). D(meas.) = 3.9-4.1 D(calc.) = 4.096 Pyroelectric, may be triboluminescent, fluorescent. Optical Properties: Transparent to translucent, opaque when iron-rich. Color: Highly variable, ranging from colorless to dark brown, gray, black, commonly brown, yellow, red, green.Sphalerite is made up of zinc sulfide, the chief ore of zinc, and is a part of the Sphalerite group. Spend $100 or More & Get 60% off - Use Code BULK60 ... Hardness: 3.5 to 4 Hardness: Numerical Vibration: Number 5, Number 6: Chemical Composition: (ZnFe)S, Zinc Sulfide: COMMON CONDITIONS:For hardness, enter only a single numerical value. Mineral Habit Color Streak Cleavage/Fracture Lustre Hardness 6 Sphalerite Euhedral Yellow Yellow Resinous 3 ...Streak brownish yellow to orange-yellow. Brittle. Sphalerite (metallic) Submetallic to resinous luster. Color yellow to yellow-brown to dark brown. Hardness=3.5-4. Perfect vleavage in six directions (dodecahedral). Brown, light yellow, to white streak. Cleavage faces common, twinning common.In a given chemical class, each mineral contains the same specific element or chemical compound but in combination with different metals. For example, galena (PbS) and sphalerite (ZnS) are both sulfide minerals, but galena contains lead and sphalerite contains zinc. The minerals of Ohio are grouped into ten chemical classes: Sphalerite. Luster: metallic or Adamentine (gem like) Hardness: 3.5-4 Cleavage: dodecahedral Streak: light yellow-brown Smells like sulfur. Pyrite. It is often coarsely crystalline or massive, or forms banded, botryoidal, or stalactitic aggregates. Sphalerite is found associated with galena in lead-zinc deposits. It occurs in hydrothermal vein deposits, contact metamorphic zones, and replacement deposits formed at high temperature (1,065°F/575°C or above).Sphalerite is a zinc ore mineral that typically contains iron. When it has a high iron content, sphalerite is an opaque black. Gem-quality material has a low iron content, resulting in transparent crystals. Due to its lack of hardness, it is mainly a collector's gemstone. One of the most notable characteristics of sphalerite is its high ...

Meaning & Energy Sphalerite is here to help ground your energies and activate your lower 3 chakras. It raises one's courage, drive, and focus levels to heights they never knew they had within. This mineral helps one truly believe in themselves, and their ability to unlock their full potential in this life.

Its Mohs hardness is 3.5 to 4. It commonly occurs as tetrahedral crystals or cubes as well as in granular or massive form. Sphalerite can be found in many ore veins of sulfide minerals, …21. Sphalerite - ZnS - Usually no problems. Pale yellow streak distinctive. Streak has “rotten egg” odor. 22. Apatite - Calcium phosphate - variable color, hardness of 5, prismatic habit (6 sided), poor cleavage parallel to base, streak always white. This is what your bones and teeth are made of. 23. Corundum - Al 2 O 3Sphalerite gem hardness Cubic Sphalerite - Gem Resource International Web30 de nov. de 2016 · The lack of hardness in this gemstone means that it can break, …Study with Quizlet and memorize flashcards containing terms like Hematite, Magnetite, Sphalerite and more. Study with Quizlet and memorize flashcards containing terms like Hematite, Magnetite, Sphalerite and more. Home. Subjects. Expert solutions. Create ... hardness:3.5-4 Streak: light yellow-brownMineral Species: Sphalerite. Mineral Group: Sulphides. Chemical Formula: ZnS. Hardness: 3.5-4. Crystal System: Isometric. Colour: Yellow, orange, light to dark brown, red-brown to black. Typical Appearance: Usually massive crystalline or as individual euhedral crystals in a wide variety of forms and associations.Hardness = 3.5-4 VHN = 208-224 (100 g load). D(meas.) = 3.9-4.1 D(calc.) = 4.096 Pyroelectric, may be triboluminescent, fluorescent. Optical Properties: Transparent to translucent, opaque when iron-rich. Color: Highly variable, ranging from colorless to dark brown, gray, black, commonly brown, yellow, red, green.This Sphalerite gemstone guide lists qualities of the Sphalerite gem type, including stone colors, common names, meanings, gemstone hardness and more. Sphalerite is a rare gemstone, so it is not often seen in jewelry. Moreover, due to sphalerite's lack of hardness, it is not recommended to be worn daily as rings or …After having a computer for a few years, your hard drive can become just as personal as a diary. Over time, you collect countless files, from pictures to documents to passwords and other personal information, that is essentially irreplaceab...Sphalerite is a mineral that consists largely of zinc sulfide in crystalline form, but it almost always contains variable amounts of iron. Its chemical formula may therefore be written as (Zn,Fe)S. ... Its hardness rating is 3.5-4 on the Mohs scale, its specific gravity is 3.9-4.1, and its refractive index is 2.37 ...

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Jul 1, 2017 · Its Mohs hardness is 3.5 to 4. It commonly occurs as tetrahedral crystals or cubes as well as in granular or massive form. Sphalerite can be found in many ore veins of sulfide minerals, commonly associated with galena and pyrite. Miners call sphalerite "jack," "blackjack," or "zinc blende." Overall, the main difference between hard and soft evidence is that hard evidence is always preferable to softer alternatives, for the simple fact that even the best soft evidence cannot outweigh hard evidence in any form.Boron nitride is a thermally and chemically resistant refractory compound of boron and nitrogen with the chemical formula BN.It exists in various crystalline forms that are isoelectronic to a similarly structured carbon lattice. The hexagonal form corresponding to graphite is the most stable and soft among BN polymorphs, and is therefore used as a …>Galena ~Chalcopyrite <Sphalerite (Hardness varies with composition) Irregular masses of Anhedral grains interstitial to Fe and Cu-Fe sulphides / Rounded inclusions in Galena and Sphalerite: Forms complete solid solution with Tennantite / Growth zoning especially in more As-rich members: Arsenopyrite Galena Sphalerite... Hardness · Chakras · Southwest Gem/ Mineral/ Rock Clubs · Taos Rockers' Gem Safari · Size Chart · About. USD, INR, GBP, CAD, AUD, EUR, JPY. 0 $0.00. USD, INR ...Faceting Sphalerite! ; Hardness, Hardness is given as 3½ to 4.[1] The name sphalerite is from the Greek word "sphaleros" which means deceiving or treacherous. This name is in response to the many different appearances of sphalerite and because it can be challenging to identify in hand specimens.Now, the mineral Sphalerite has a hardenss of about 3.5-4. Meaning, depending on how hard it really ends up being, it will be on the lower end of the hardness scale. If it was at the 3.5 hardness: it would be able to be scratched by anything over the 3.5 hardness. Including a copper coin. It would be between the hardness of Calcite and Fluorite. ….

Its hardness rating is 3.5-4 on the Mohs scale, its specific gravity is 3.9-4.1, and its refractive index is 2.37 (when measured using sodium light at 589.3 nanometers). Its …MOHS Hardness Scale. MOHS Hardness Scale. Chemical Composition. ZnS. Healing Properties. Sphalerite fills the body with golden light and imparts an inner sense ...Hardness: 3.5 to 4: Specific gravity: 4.0: Cleavage: Perfect dodecahedral {110} Fracture: Conchoidal: Luster: Adamantine Resinous: Transparency: Transparent to opaque: Streak: White to brown or yellow: Optical Properties: PPL: Colorless to pale brown ... As sphalerite is isotropic, this video is uneventful. Sphalerite in plane polarized light.Sphalerite is a zinc ore and has a Mohs hardness of 3.5-4, which makes this gem a little bit of a softie. It is best to keep this metal-based gem away from ...Characteristic Physical Properties Chemistry & Crystallography Common Name Sphalerite Species Sphalerite Sphalerite Colors Black Brown Gray Green Green Multi-color …Mustafa Özer. This paper reports the results of flotation tests conducted with a copper-lead-zinc sulphide ore. The major sulphide minerals in the ore are chalcopyrite, galena, sphalerite ...Wurtzite is a zinc and iron sulfide mineral with the chemical formula (Zn,Fe)S, a less frequently encountered structural polymorph form of sphalerite.The iron content is variable up to eight percent. It is trimorphous with matraite and sphalerite.. It occurs in hydrothermal deposits associated with sphalerite, pyrite, chalcopyrite, barite and marcasite.It also …hardness: 5-6. Pyroxene . calcite hardness- 3. Fluorite hardness-4. Orthoclase hardness- 6. Sulfur hardness 1.5-2.5. Galena hardness- 2.5-2.8 very dense- 7-8. copper hardness 2.5 - 3. Pyrite hardness- 6-6.5. Halite hardness-2.5.About sphalerite – introduction and history. Sphalerite is a zinc ore containing iron When its iron is high, its color becomes matte black Materials that have the quality of jewels have less iron content and as a result their crystals are transparent. Due to its low hardness, it is considered a gem for collectors Sphalerite hardness, The most common type of coal is anthracite, which has a hardness of 2.2 when compared to the Moh’s scale of mineral hardness, according to the Ted Pella website. However, since coal is not a mineral, it is not officially measured in this wa..., Fig. I shows a polished surface of a hand specimen of the material involved in most of the experiments--a highly coherent galena-sphalerite-garnet gneiss ..., 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 ... , Sphalerite presents great challenges to the gem cutter due to its lack of hardness, perfect cleavage and brittle nature. Yet, once a gem has been properly ..., Composition The chemical formula (Zn, Fe) of sphalerite is S. It is a zinc sulphide containing a variable amount of iron instead of zinc in the mineral lattice., Now, the mineral Sphalerite has a hardenss of about 3.5-4. Meaning, depending on how hard it really ends up being, it will be on the lower end of the hardness scale. If it was at the 3.5 hardness: it would be able to be scratched by anything over the 3.5 hardness. Including a copper coin. It would be between the hardness of Calcite and Fluorite., Sphalerite. Sphalerite is the major ore of zinc. It is a sulphide mineral and exhibits a wide range of physical properties, such as colour, transparency, streak and lustre, because many elements can substitute for Zn in its crystal structure. Iron is the principle substituent, but cadmium, gallium and iridium can also substitute to economic ... , Hardness: 6 – 6.5, brittle nature: Specific Gravity: 5 or above (feels heavier than average, even for a metallic mineral) Luster: ... volcanic rocks of northern Wisconsin and northern Minnesota where it is associated with massive chalcopyrite and …, Sphalerite Mineral Facts: · Colors: Usually Black, Brown or some shade of Red, may be yellowish or green. Its streak is brownish, yellow or white. · Hardness: 3.5 ..., Due to its lack of hardness, it is mainly a collector's gemstone. One of the most notable characteristics of sphalerite is its high dispersion (0.156). In fact, the dispersion of sphalerite is over three times that of diamond, which has a dispersion of 0.044., Two minerals of note have differences in hardness depending on direction: Kyanite has a hardness of 5 parallel to the length of the crystal, and a hardness of 7 when scratched along a direction perpendicular to the length. Calcite has a hardness of 3 for all surfaces except the {0001} plane. On {0001} it has a hardness of 2., Siderite belongs to the calcite group of minerals, a group of related carbonates that are isomorphous with one another. They are similar in many physical properties, and may partially or fully replace one another, forming a solid solution series. All members of the calcite group crystallize in the trigonal system, and have perfect rhombohedral ..., Sphalerite is a zinc ore mineral that typically contains iron. When it has a high iron content, sphalerite is an opaque black. Gem-quality material has a low iron content, resulting in transparent crystals. Due to its lack of hardness, it is mainly a collector's gemstone. One of the most notable characteristics of sphalerite is its high ..., 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. ... Hardness: 3.5–4 Amount of …, C) hardness and streak D) streak and cleavage 40.Which two properties are most useful in distinguishing between galena and halite? A) shale B) phyllite C)dunite D) schist 41.A nonvesicular rock is made entirely of green 2-millimeter-diameter crystals that have a hardness of 6.5 and show fracture, but notcleavage. The rock is most likely A ..., With a hardness of just 3.5 to 4, sphalerite can be scratched very easily. Common household dust, with a hardness of 7, would scratch sphalerite if you wiped it off with a cloth. Faceters also face additional challenges …, Two minerals of note have differences in hardness depending on direction: Kyanite has a hardness of 5 parallel to the length of the crystal, and a hardness of 7 when scratched along a direction perpendicular to the length. Calcite has a hardness of 3 for all surfaces except the {0001} plane. On {0001} it has a hardness of 2., Sphalerite . Massive brown sphalerite which in reflected light displays a silvery grey colour. About this collection . Metalliferous Ores. This small demonstration collection contains …, Have you noticed a white residue on your clothing and cooking pots and wondered if you need water softening equipment? Here’s a look at how to test the hardness of water. Water softening technology is commonplace in water treatment faciliti..., With a hardness of just 3.5 to 4, sphalerite can be scratched very easily. Common household dust, with a hardness of 7, would scratch sphalerite if you wiped it off with a cloth. Faceters also face additional challenges cutting this stone. It has six perfect cleavage planes in its isometric crystal structure and it’s brittle. , Advertisement ­You can buy a new hard drive from many different places: a retail store, a large computer store, a local computer parts store or by mail order. Wherever you go to buy it buy it, keep three things in mind: Now that you have yo..., Zinc ; Type. Element (Minerals/Ores of) ; Mineral Classification. Sulfide ; Chemical Formula. (Zn,Fe)S (sphalerite) ; Mohs Hardness. 3.5-4 ..., Sphalerite is a relatively soft gem, with a hardness of only 3.5 to 4 on the Mohs scale, about the same as fluorite. So despite its amazing fire, it is not suitable for everyday-wear rings. It has a density or specific gravity of 3.90 to 4.10, making it one of the denser gems, similar to sapphire and ruby, but not quite as dense as zircon., Sphalerite is a sulfide mineral with the chemical formula S. It is the most important ore of zinc. Sphalerite is found in a variety of deposit types, but it is primarily in sedimentary exhalative, Mississippi-Valley type, and volcanogenic massive sulfide deposits. It is found in association with galena, chalcopyrite, pyrite , calcite, dolomite, quartz, rhodochrosite, and …, Hardness: 2 Cleavage: Good in 1 poor in 2 Luster: Vitreous, pearly or silky Tenacity: Flexible Diaphaneity: Transparent to opaque ... Sphalerite. Hardness: 3.5 - 4 Cleavage: 6 directions Luster: resinous (root beer) Streak: light …, 3.5 - 4 White to Perfect in six directions 4 Fine to coarse granular masses. Tetrahedron Sphalerite yellowish- shaped crystals. Yellowish-brown to black color. ZnS brown Resinous luster. 5 - 6 Reddish- None. Uneven fracture. 5 Massive, granular. Reddish-brown, gray to black Hematite brown color. Can have metallic luster or earthy red color. Fe O 23, May 1, 2023 · Sphalerite is a widely studied specimen. It has the ability to form on dolomite, giving it an attractive resinous luster that sets it apart from other minerals in its group. Its hardness (3.5 to 4) and distinct features make sphalerite a one-of-a-kind gemstone that can be found throughout many parts of the world. , Sphalerite’s 3.5-4 hardness ranking means even household dust (at 7 hardness) can scratch it. Therefore, we recommend sphalerite pendants or brooches …, 27 Nis 2021 ... Hardness of Stone. As mentioned above, one of the physical properties of stone is its hardness. In previous blogs, I have briefly mentioned ..., C) hardness and streak D) streak and cleavage 40.Which two properties are most useful in distinguishing between galena and halite? A) shale B) phyllite C)dunite D) schist 41.A nonvesicular rock is made entirely of green 2-millimeter-diameter crystals that have a hardness of 6.5 and show fracture, but notcleavage. The rock is most likely A ..., Although it’s too fragile for making jewelry because of its 3.5 to 4.0 rating on the hardness scale, collectors find it a magnificent crystal. This crystal usually comes in …, Sphalerite. Hardness: 3 ‐ 4 Cleavage: 6 directions Luster: Resinous Streak: Light yellow Tenacity: Brittle Diaphaneity: Opaque Composition Group: Sulfide Use: Zinc ore. ... Hardness: Fracture: Uneven to conchoidal Crystal Habit: 12 sided crystals (dodecahedral) Luster: Vitreous to resinous Tenacity: Brittle Diaphaneity: Opaque Composition ..., Hardness: 3.5 to 4: Specific gravity: 4.0: Cleavage: Perfect dodecahedral {110} Fracture: Conchoidal: Luster: Adamantine Resinous: Transparency: Transparent to opaque: Streak: White to brown or yellow: Optical Properties: PPL: Colorless to pale brown ... As sphalerite is isotropic, this video is uneventful. Sphalerite in plane polarized light.