The main diagnostic feature for the sample is the

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The main diagnostic feature for the sample is the vitreous luster and the conchoidal fracturing.Quartz isknown for having a vitreous/glassy luster. Also, quartz is known for having conchoidal fracturing whichresembles curved ridges.The hardness is also a distinct feature because seven is the hardness of quartz.Using another known sample of quartz, I can scratch the sample and the sample can also scratch the quartz.Since two minerals of the same type can scratch one another, this is a reasonable conclusion. The color of thesample leads me to believe that the mineral is not only quartz, but is a variation called smoky quartz.Identification and Formula: Quartz var. Smoky quartzSiO2Streak: WhiteThis mineral is a combination of white, light gray, and light green coloringwith a non-metallic pearly luster.The streak is a white color and the density is normal. The hardness is between 5.5 and 7. The habit for thissample is massive.For this sample, the cleavage is prominent. However, some of the cleavage is perfect, andsome is imperfect.The hardness is determined to be between 5.5 (hardness of glass) and 7 (hardness of a ceramic plate)because the sample is able to scratch glass but is not able to scratch a ceramic plate.The cleavage at nearly 90 degrees and the hardness mixed with the monoclinic crystal form are distinguishingfactors that lead me to believe that this sample is Microcline. Though this sample is a green color, I am notsure if it is green enough to be called Amazonite which is a variation of Microcline and Orthoclase.Identification and Formula: OrthoclaseKAlSi3O8Streak: whiteThe mineral is a combination of red and orange coloring with a non-metallic earthy/dull luster. The streak iswhite and the density is heavy. The hardness is between 3.5 and 5.1 and the habit is granular. The mineraldoes have cleavage, but the cleavage on the top and bottom are poor and the sides have decent cleavage.The cleavage is most likely rhombohedral. The sample is not magnetic, and since the mineral has rust, it mostlikely contains iron.
Mineral IdentificationNicole MerriweatherReasons for Identification:Outside sampleSample 19Luster: earthyDensity: heavyHardness: 5.5-7Lab SampleCleavages: imperfectColor: red/brown blackOther:Habit: massiveDescription:Reasons for Identification:Outside sampleSample 20Luster: NM-PearlyDensity: heavierHardness: 5.5-7Lab SampleCleavages: perfect 3DOCColor: whiteOther: slightly heavier than normalHabit: massiveDescription:Hardness is determined between 3.5 (hardness of a penny) and 5.1 (hardness of a knife) because the samplecannot be scratched by a penny, but it can be scratched by a knife.The diagnostic features for the sample are the color, higher density, rhombohedral cleavage, and the whitestreak. All of these factors lead me to believe that the mineral is Siderite. On most samples of Siderite, thecolor is more brownish red. For the most part the lab sample is a darker brownish-red. This is possiblybecause it has been exposed to the air for a longer amount of time.The rust on the sample narrowed down

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Term
Spring
Professor
William I Manton
Tags
Mineralogy, Luster

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