Dolomite is a type of limestone that contains magnesium crystals. Granite Hardness on the Mohs Scale for Stone Strength Falling closely behind diamonds on the Mohs scale are corundum (9), titanium (9) and topaz (8). The calcium from limestone is the major contributor to the hardness of Woodbury's water. Water Softening | Woodbury, MN ... Hardness â Generally hard. This is because most hardness and alkalinity come from limestone or dolomite sources in nature. Limestone hardness terms of carbonate (temporary) and noncarbonate (permanent) hardness. Chapter 4 Engineering Classification of Rock Materials 2.2â2.8. While the size of the grain may vary due to the presence of fossil fragments and mineral deposits, limestone is primarily composed of calcite, giving it a fine, chalky texture. To see why, consider the following chemical equation: Calcium. Question: What Is The Hardest Mineral According To Mohs ... Sandstone, on the other hand, is not described as coming from any one substance. Limestone. Hardness is caused by compounds of calcium and magnesium, and by a variety of other metals. Hardness Absolute Hardness: 2. 3 = Calcite. Sources The principal natural sources of hardness in water are dissolved polyvalent metallic ions from sedimentary rocks, seepage, and run-off from soils. Champagne White limestone is also a brilliant shade, but it has a smoother finish and is a more durable stone. There are many different types of limestone formed through a variety of processes. Rocks don't technically have any concrete MOHS hardness as they are mixtures of minerals. Hardness of Water | U.S. Geological Survey When it comes to classifying a natural stone (granite), before making a purchase, stone buyers like to focus on the relative granite hardness to know how hard a stone is in comparison with other natural stone products like marble, sandstone, slate, limestone, and quartzite. Limestone may form from chemical processes instigated by large populations of algae, or may form as the shells from aquatic creatures and single-celled organisms form a dense layer. When water flows over limestone, _____ is dissolved, creating hard water. The hardness of Limestone is 3-4 whereas its compressive strength is 115.00 N/mm 2. 2: Gypsum: Plaster of paris. Limestone is a sedimentary rock that is composed primarily of calcite (calcium carbonate, CaCO 3) and dolomite (calcium magnesium carbonate, CaMg (CO 3) 2 ). Limestone paving slabs have a noble and elegant natural texture and colours with very high density, and their pores are less than other stones, so the hardness of limestone is very high. The most common sources of hardness are limestone (which introduces calcium into the water) and dolomite (which introduces magnesium.) Water hardness may Granite, for example, can have a quartz content anywhere between 20% and 60%. In general, limestone is defined as being composed of calcium carbonate. minerals. and hardness originate from the dissolution of geological minerals into rain and groundwater. Limestone is composed mostly of the minerals calcite and aragonite, which are different crystal forms of calcium carbonate (CaCO 3). The principal natural sources of hardness in water are sedimentary rocks and seepage and runoff from soils. â¦. 55, January 2012) 4âv. Its natural surface gloss and anti-slip properties make limestone ideal for outdoor garden and patio paving. This is because it will release calcium and some other beneficial mineral contents in your water. When limestone and dolomite dissolve in water, one half of the molecule is calcium or magnesium (the "hardness") and the other half is the carbonate (the "alkalinity"). 2.7â2.8. Calcium, Ca2+ Calcium, in the form of the Ca2+ ion, is one of the major inorganic cations, or positive ions, in saltwater and freshwater. 55, January 2012) 4âv. Cubic cleavage. It is one of its abilities that play a decisive role in selecting or rejecting the stone. However, the calcite in limestone often contains a few percent of magnesium. Limestones were used in Saqsaywaman where the Yunkaypata limestone formation is â¦. Shale. 2.4â2.8. The higher grinding coefficient, the more grinding of this material. from publication: ⦠Well, Limestone is a type of sedamentery rock, and marble is a form of metamorphic rock, which is formed by the heating and crystalisation of limes... It can vary in purity, consistency and hardness. The Brinell hardness number is computed from the equation: Hardness of Limestone is approximately 4 Mohs. 2.7â2.8. Hardness is determined by the ability of one mineral to scratch another. Limestone is mainly calcium carbonate(CaCo3), when it is heated it is decomposed in calcium oxide(cao) and cabon dioxide(Co2).It is a valuable natu... The increased value of Schmidt rebound hardness highest energy was used up for crushing of magma rocks causes the fall of impact energy, which means that the diabase and spilite and the lowest energy for crushing of rocks of larger hardness will need less impact energy for sediment rocks dolomite and limestone. What is the Hardness of Granite? To test for hardness with any of these items, two approaches Calcite is an anhydrous carbonate, and one of the most widely distributed minerals on the Earth's surface. Calcium carbonate often comes from plant and animal skeletons and remnants including the shells of mollusks. Limestone is a sedimentary rock composed largely of the minerals calcite and â¦. is hard, durable, and commonly occurs in easily accessible surface exposures. Download scientific diagram | -Brinell hardness number (BHN) of different shales, coal, and Carthage limestone (Grieser, 2009). This is an excellent raw material for cement production. It is easy to confuse hardness with alkalinity because both are measured in ppm CaCO 3 and both often enter the water from limestone. Limestone-Hardness What order do limestone,granite and marble in terms of their hardness? 4 = Fluorite. This is partly due to different rocks of the same type containing different proportions of minerals. All natural materials are graded on The Mohs Hardness Scale. The hardness grade of natural limestone samples is up to the half-hard grade. True or False: Water hardness is divided into four categories, depending on the concentration of calcium carbonate in the water. There are many different types of limestone formed through a variety of processes. Gypsum is formed when seawater evaporates from the Earthâs surface. The hardness is about 6 and the specific gravity between 2.5 2.8. Limestone is a sedimentary rock composed primarily of calcium carbonate (CaCO3) in the form of the mineral calcite. It most commonly forms in clear... Limestone and soapstone can both be fantastic additions as countertops or accent pieces in homes, apartments, and businesses. Color lead-gray. Each of these materials has different grinding coefficient. Table 2. Limestone, Calcium carbonate, found just about everywhere in Tennessee, was declared the official state rock in 1979. This method of hardness judgement is based on the ability of one sample of matter to scratch another. However, a more accurate 3: Calcite: Limestone and most shells contain calcite. Mohs' Hardness (Typical) of Abrasives table from READE. The hardness of water is determined by the milligrams of calcium carbonate per litre and is reported it in parts-per-million (ppm). Answer (1 of 2): Limestone is a soft, easily workable rock that is comprised of at least 50% calcite, aragonite, and/or dolomite. Common application rates for limestone are 1 to 2 tons per surface acre. Limestone Classification Limestone is a sedimentary stone with 50% by weight calcite or calcium carbonate (CaCO3) content. For comparison, a typical steel steak knife is around 5.5 and cannot scratch granite but could scratch marble, travertine or limestone. Total water hardness is usually expressed as the milligrams of CaCO3 equivalent to the total amount of calcium and magnesium present in one liter of water (mg/liter, i.e., ppm). Shale. Ferberite Galena is also found in limestones either as veins or as a replacement deposit. hardness of water.ppt - HARDNESS OF WATER You need to know the details for calcium This is a \u2018limestone pavement\u2019 Limestone is calcium carbonate it Luster of Limestone is dull to pearly. Rain water is naturally soft but hard water is formed when water passes through or over limestone or chalk and calcium and magnesium iron dissolve into the water. Limestone is a sedimentary rock consisting of more than 50% calcium carbonate ( calcite - CaCO 3 ). The Brinell hardness number (HB) is the load divided by the surface area of the indentation. Schist is a composite material made up of a mixture of several minerals, each of which have different mohs hardness. Diamond is the hardest substance found on earth in so many natural forms, and it is an allotrope of carbon. The Mohs scale is for natural minerals. For manufactured products other measures of hardness are better. Diamond is always at the top of the scale, being the hardest mineral. There are ten minerals in Mohs scale, talc, gypsum, calcite, fluorite, apatite, feldspar, quartz, topaz, corundum, and for last and hardest, diamond. As mentioned above, the principal causes of water hardness are calcium and magnesium minerals. Mesozoic ones; they have 5° of hardness and a compression resistance of 800 Kg/cm². Shell Reef natural limestone starts out as a bright white that will soften slightly with age and use. Actual property values will vary from sample to sample. Streak lead-gray. Limestone is naturally a light and bright color, and youâll love how it can brighten up a room. Scientists test natural rock to see if it is limestone by pouring cold diluted hydrochloric or sulphuric acid (10% solution or vinegar) on it. Texas Holey Rock is the commonest type of limestone used in ⦠3. the streak of limestone. The result is this ordinal scale of minerals by hardness, with 1 being the softest and 10 being the hardest. This aquifer is full of limestone, which in turn leaves dissolved minerals in our water. Hardness 2.5. It can withstand a lot of wear and tear and still look good. The study of the limestone hardness in the Kef area showed that all Aptian limestone deposits are able to cross the limit of hard field according to [25] . The higher the number, the harder the mineral. While you cannot have a countertop made out of diamonds, there are still many great options for hard stone countertops. The San Antonio Water System says that some areas of limestone are denser than others, so water hardness can vary in different parts of the community. Streak white to gray. Streak is the color of rock when it is crushed or powdered. These minerals occur naturally as ionic salts (primarily as bicarbonates, sulfates, nitrates, and chlorides) in sedimentary rocks such as ⦠Limestone hardness refers to the soft or hard and smooth mineral structure of limestone crystals. 2.4â2.8. It can originate from the dissociation of salts, such as calcium chloride or calcium sulfate, in water. Galena (PbS) Luster bright metallic. (geology) a very widely distributed crystalline form of calcium carbonate, CaCO 3, found as limestone, chalk and marble. Property values are typical of Limestone used in construction. Anionic dispersants, including phosphates and acrylates, are used as grinding aids and to make the resulting slurry more stable in a colloidal sense. The scale arranges the minerals in order of increasing hardness. The water hardness is expressed by an index, or total hardness, TH, in degrees, each degree determined by the following formula: 1 degree (°F : French unit) = 4 mg/liter of calcium or 2.43 mg/liter of magnesium or 10 mg of limestone. These results were confirmed by [26] who reported a hardness value rating of 7 to 8 and a compressive strength of 662 bars and a specific gravity of 2.54 g/cm 3. table 4: rockwell and mohr hardness of the limestone samples S/N Rockwell Mohr Hardness 1 79.2 3.0 4. Pure Limestone consists entirely of the mineral Calcite, CaCO3, that is Calcium Carbonate. The Hardness (H) of Calcite on Mohosâ Scale of Hardness... Most limestone is grey, but all colours of limestone from white to black have been found. At the temperature lower than 500 °C, the samples are still half-hard in spite of a decrease in the Protodyakonov scale of hardness. The hardest mineral on the Mohs scale is diamond, which ranks at a 10. Material Notes: Sedimentary rock; critical mineral is calcite (CaCO 3, calcium carbonate, 90-100%). This scale was invented by German mineralogist Friedrich Mohs in 1812, and ranks minerals based on their ability to scratch or sustain scratches. This is partly due to different rocks of the same type containing different proportions of minerals. The hardness of diamond is the highest level of Mohs hardness â grade 10. Its microhardness is 10000kg/mm2, which is 1,000 times higher ⦠Minerals that can be scratched by the fingernail range from 1 to 2.5 in hardness; by a penny 2.5 to 3.5; Properties Of Limestone Physical Thermal Rocks with hardness 13 are soft rocks from 36 are medium hardness rocks and 610 are hard rocks. Limestone, marble, caliche, veins of calcite, hard-water deposits on plumbing fixtures. Below is the hardness score of different natural stones on the Mohs Scale. It stands above the landscape in outcrops that resist erosion. Differences between Limestone and Dolomite. Luster of Limestone is the interaction of light with the surface of Limestone. The Dolomite is slightly more complex than limestone. Chief raw material for cement, wide variety of other uses. Limestone is a fine grained stone that comes in a variety of golden, earthy colors as well as white and dark brown. Hardness: Mineral: Associations and Uses: 1: Talc: Talcum powder. The usual cementing material in sandstone is calcium carbonate, iron oxides, or silica, and the hardness of sandstone varies according to the character of the cementing material; quartz sandstones cemented with quartz are the hardest.In sandstones, sand is between 1/16 millimeter and 2 mm in size (silt is finer and gravel is coarser). Limestone is a sedimentary rock consisting of more than 50% calcium carbonate ( calcite - CaCO 3 ). It is a common constituent of sedimentary rocks. As mentioned above, the principal causes of water hardness are calcium and magnesium minerals. Most calcium in surface water comes from streams flowing over limestone, CaCO3, gypsum, CaSO4â¢2H2O, and other calcium-containing rocks and ⦠The MOH'S hardness of limestone is 3. If you strike a piece of calcite with a hammer, it will split into many small rhombohedrons along its cleavage planes. The hardness of marl is lower than the hardness of limestone The more clay substances, the lower its hardness. Limestone is ideal for high traffic areas. We get our water from the areaâs largest water source, the Edwards Aquifer. Since, hardness enters the water in this manner groundwater generally has a greater hardness than surface water. Rainwater is naturally acidic, which tends to solubilize some minerals more easily. Reacts with dilute HCl acid. Federick Mohs, a German mineralogist, produced a hardness scale, using a set of ten standard minerals. Calcite 3.5 Limestone They are also common essential mineral constituents of food. Limestone. As you can see, rocks of the same type can have a range of densities. A ranking of 1 means the mineral is very soft, while a ranking of 10 means it is very hard. Table 4Dâ6 Hardness and unconfined compressive strength 4Dâ3 Table 4Eâ1 Line survey data 4Eâ1 Table 4Eâ2 Joint set spacing categories 4Eâ1 Part 631 National Engineering Handbook Engineering Classification of Rock Materials Chapter 4 (210âVIâNEH, Amend. Liming can also be used to increase the hardness of water by the addition of calcium and magnesium. General guidelines for classification of waters are: 0 to 60 mg/L (milligrams per liter) as calcium carbonate is classified as soft; 61 to 120 mg/L as moderately hard; 121 to 180 mg/L as hard; and more than 180 mg/L as very hard. The diameter of the impression is measured with a microscope with a superimposed scale. The most preferred materials were rocks of igneous or volcanic origins, being â¦. Indiana Limestone is Americaâs most-used wall cladding stone. Water hardness The hardness of water is due to the presence of calcium and magnesium minerals that are naturally present in the water. 4: Fluorite: Fluorine from fluorite prevents tooth decay. ... Limestone is a critical resource for the construction industry. This means that the level of water hardness and alkalinity in a place will be very similar. Formed from the condensed layers of ancient coccoliths and foraminifera remains, the soft white mineral rates a 1 on Mohs Hardness Scale. Limestone is calcium carbonate, and dolomite is a combination of calcium carbonate and magnesium carbonate. Limestone and Dolomite are used in the manufacturing of desulfinators and neutralizers for cleaning industrial waste. Click on an area without a City to open a pop-up box detailing the average State water hardness. the hardness of limestone is 34 whereas its compressive strength is 115.00 nmm 2. streak is the color of rock when it is crushed or powdered. Basalt is the most abundant of extrusive rocks, it is the volcanic â¦. Many of the world's largest chalk deposits began forming up to 65.5 million years ago during the Cretaceous Period. Slate. To give you an idea of how durable the stones in our staircases and fireplaces are, we have added them to our revised version of the hardness scale: The Mohs Scale of Mineral Hardness 1. The usual signs of a : Granite, marble, then limestone, hardest to softest. Adding limestone to your aquarium water can help to increase the hardness of your water. Granite, for example, can have a quartz content anywhere between 20% and 60%. sodium chlorine carbon calcium. Chalk, a type of limestone, makes up the white cliffs of Dover. The granite hardness helps buyers make a balanced decision. Limestone. Sandstone is a rock made of sand, and sand is material within the narrow size range of âsandâ, which is between silt and gravel. Sandstone - as a r... It has vitreous luster and perfect cleavage in three dimensions. Marble, Travertine and Limestone are generally 3-4 on the Mohs scale while Granites are generally 8-9. For years, tests have concluded that high-performance coatings provide excellent corrosion protection and durability when applied over a blast-cleaned surface with a consistent anchor profile. While individual water softening is not necessary, many individuals choose to have private water softeners. Limestone Categories: Ceramic. Calcite defines the hardness 3 on Mohs scale with specific gravity 2.71 g/cm 3. Limestone comes in many colors and textures, depending on its precursors. Limestone is a soft, easily workable rock that is comprised of at least 50% calcite, aragonite, and/or dolomite. Rocks don't technically have any c... As a result, marble is less porous and slightly stronger than limestone, but still less durable than granite. In the Texas area, most of the crushed rock used for concrete is crushed limestone, crushed concrete, or a smooth river rock. Limestone is formed by a number of natural processes including the settling of calcium deposits in subterranean caves, as well as from the slow compression of fossilized coral, shells and microorga⦠Chert is as hard as crystalline quartz with a hardness rating of seven in the Mohs scale â maybe a bit softer, 6.5, if it still has some hydrated silica in it. The hardness of any mineral is rated on a 1 to 10 scale called the Mohs scale. 5: Apatite: Apatite is a mineral in vertebrate bones and teeth. hardrock and soft rock are the terms which are not commonly used in geology as reference .. as far as hard rock is concerned the rocks with ability... Since sandstone is made up of many small sand particles, it will break apart fairly easily while limestone is much harder and should not crumble . references Sandstone Physical Properties However, as temperature reaches 600 °C, the Protodyakonov scale of hardness of the rock samples reduces to soft grade. More confusion exists between hardness and alkalinity than any of the other water quality parameters. Gypsum 3. Beyond simply being hard, chert is a tough rock. Table 4Dâ6 Hardness and unconfined compressive strength 4Dâ3 Table 4Eâ1 Line survey data 4Eâ1 Table 4Eâ2 Joint set spacing categories 4Eâ1 Part 631 National Engineering Handbook Engineering Classification of Rock Materials Chapter 4 (210âVIâNEH, Amend. The Mohs hardness scale measures a mineral's resistance to scratching. Sandstone. Footnote 4 Groundwater is generally harder than surface water. So a mineral ranked 8 out of 10 is harder and will scratch a mineral ranked 3. A mineral that can scratch calcite, hardness 3, but will not scratch fluorite, hardness 4, is rated a hardness of 3.5. Absolute Hardness: 9. Almost all limestone is composed of grains or fragments of biologic origin, ranging from fossils or organically derived ⦠Both limestone and marble are soft stones, falling at the lower end of the Mohrâs Hardness Scale. This quality makes them easier and less expensive... Marble, Travertine and Limestone are softer than other natural stones like granite and will scratch more easily than granite. All natural materials are graded on The Mohs Hardness Scale. Marble, Travertine and Limestone are generally 3-4 on the Mohs scale while Granites are generally 8-9. This aquifer is full of limestone, which in turn leaves dissolved minerals in our water. The knife blade is particularly useful in separating the common harder minerals (quartz and the feldspars) from the common softer minerals (calcite and dolomite). table 4: rockwell and mohr hardness of the limestone samples S/N Rockwell Mohr Hardness 1 79.2 3.0 In general, hard waters originate in areas with thick topsoil and limestone formations. Oil drillers dread it because itâs so hard to penetrate. Limestone noun. Crushed Limestone Rock: There are other uses for Crushed Limestone Rock such as: Road Base Abrasive blasting for surface preparation is an important step in providing a foundation for protective coatings. Slate. Woodbury's water hardness is approximately 13.5 grains. As mentioned above, a minor contribution to the total hardness of water is also made by other polyvalent ions, such as aluminium, barium, iron, manganese, ⦠The San Antonio Water System says that some areas of limestone are denser than others, so water hardness can vary in different parts of the community. Calcite noun. Limestone is most abundant through middle Tennessee and is found in scattered areas through eastern Tennessee. The streak of Limestone is white whereas its fracture is splintery. Sandstone. See also: Hardness of Materials Example: Strength Limestone is a sedimentary rock such as greater than 50% calcium carbonate ( calcite â CaCO3). In fact, when limestone is the only cause of hardness and alkalinity in water, the amount of alkalinity and hardness in the water should be about the same. Cleavage rhomb shaped. Calcite in limestone is divided into low-magnesium and high-magnesium calcit⦠However, commercial limestone usually has more than 50% calcium carbonate. Minerals are unique identifiable naturally occurring crystalline solids. They have a defined composition and internal structure. Rocks are MADE of... Since, hardness enters the water in this manner groundwater generally has a greater hardness than surface water. striped bass require hardness levels above 100 ppm, and a minimum hardness of 200 ppm is required for production of redfish. The Mohs Scale of Hardness was created in 1812 by German geologist/mineralogist Friedrich Mohs. 2. True _____ is an indicator used in titrations for determining water hardness. We get our water from the areaâs largest water source, the Edwards Aquifer. Since travertine is a softer product, it is not as suitable for floors as much as limestone, but it can be stunning as a backsplash, on countertops and along walls. Fluorite is a mineral composed of calcium fluoride. Groundwater that has been in contact with porous rocks containing deposits of minerals like limestone or dolomite will be very hard, while water from glaciers or flowing through igneous rocks is much softer. being limestone and chalk. Calcium carbonate is a chemical compound with the formula Ca CO 3.It is a common substance found in rocks as the minerals calcite and aragonite (most notably as limestone, which is a type of sedimentary rock consisting mainly of calcite) and is the main component of eggshells, snail shells, seashells and pearls.Calcium carbonate is the active ingredient in agricultural lime and is ⦠Depending on the limestone and the mineral combination within the marble, most marble rates from three to five on the Mohs hardness scale. In crystallized form, Calcite has a vitreous lustre. Tennessee marble, as the metamorphic version of limestone is known, is widely used in public and private buildings. The most common sources of hardness are limestone (which introduces calcium into the water) and dolomite (which introduces magnesium.) Buildings using it exist in every American city, in most smaller towns and villages, in Canada, and in every type of atmosphere. Dolomite, CaMg(CO 3) 2, is an uncommon mineral in limestone, and siderite or other carbonate minerals are rare. Minerals do have defined hardnesses though. Click the arrow that is located at the top left corner of the map to zoom-out. Surface and groundwater sources in areas with limestone formations are especially likely to have high hardness and alkalinity due to the dissolution of bicarbonates and 2.2â2.8. Also shown on the graph is the relative hardness of several common items that can be used to separate the minerals. Agricultural and horticultural limestones are considered soft crystals, reacting quickly with acid, which are more desirable in adjusting the pH of substrates formulated with peat moss, pine bark or coconut coir. Hardness 3. What Is Limestone Hardness inmoh.net. Measures of water hardness. Table 2. On the other hand, the softest is talc, which ranks at a 1. Stone hardness is very important as there is a correlation between stone hardness and strength of the finished concrete. There are many exceptional kinds of limestone formed thru a ramification of tactics. The hardness of stone is measured by Mohs hardness as a unit of calculation, Mohs hardness in the 6~7 (F=14~20) are hard stone, such as Quartzite and Granite; Mohs hardness between 3 to 5 (F=8~14) belong to the medium-hard stone, such as Marble; Mohs hardness in 1~2 (F=2~6) are soft stone, such as limestone and dolomite etc. Dv kg/mm(sq) = 0.08 Rc (bars); Dv = 8 Rc (bars). Limestone gives off bubbles of carbon dioxide. Because of the hardness of limestone, the grinding process is energy-intensive. Limestone is a âclasticâ sedimentary stone. The minerals that compose limestone (calcite, aragonite, dolomite, etc.) usually originate as precipitated byproducts of marine creatures. These or... These minerals occur naturally as ionic salts (primarily as bicarbonates, sulfates, nitrates, and chlorides) in sedimentary rocks such as ⦠An abundant rock of marine and fresh-water sediments; primarily composed of calcite (CaCO 3 ); it occurs in a variety of forms, both crystalline and amorphous. Talc 2. Calcite has a ⦠responsible for hardness, and total water hardness is defined as the sum of the calcium and magnesium concentrations. Limestone is a rock made of calcite. Click on a City to open a pop-up box detailing its water hardness. Water Softening. Mohs Scale of Hardness. #2 The Pros and Cons of Stone Hardness on Your Design. As you can see, rocks of the same type can have a range of densities. The use of cutting boards will help this greatly. Marble is limestone that has been compacted and heated over millions of years. Click on a State to zoom-in. Limestone and Sandstone Composition. For Indian sandstone suppliers, limestone exporters, marble exports, Mohs scale is undeniably the most widely chosen approach to test a materialâs hardness. The application of this method to the measurement of the hardness of limestone shows, besides the influence of the rock structure one gets a simple connection between the hardness and the compressive strength. The hardness of an unknown mineral may be determined by comparison with a mineral of a graded series of known hardness. Find the traditional scale here and a chart of select gems ordered by hardness.
Sing Full Movie Dailymotion, How To Reverse Rotation On A Single Phase Compressor, Voyage Au Bout De Lenfer Netflix, Someone Pinch Me, I Must Be Dreaming Meaning, Size 5 Capsule Holding Tray,