Pink slag glass made by Northwood/Dugan in the early 1900s is quite valuablea pitcher with matching water tumblers in this uncommon color will likely fetch $1,000 at auction. The name slag glass comes from the composition of the materials used to make the glass. The marbling should be a creamy white color that is evenly mixed into the base color. How Much Is Slag Glass Worth? $75.00 + $67.15 shipping. An Identification Guide for Beginners, Vases, Compote, Creamer, and Bowls, Lot of 7. All Listings filter applied; Delivery Options. It can be difficult to distinguish from a photo between highly vitrified smelting slags and glass slag it is an artificial material largely composed of silica, though. Sowerby, a popular pressed glass manufacturer in the UK during this time frame, was the first manufacturer to start producing slag glass. The older piece, the greater value it has. One of the most common alternate names for slag glass is marble glass, for obvious reasons. An Art Nouveau Slag Glass Lamp and Reverse Painted Glass Lamp, The slag glass lamp with art nouveau design with cream and amber color glass in good condition with some surface air bubbles and pitting but no visible cracks or breaks, there is some solder tot the top to reinforce the seams, worn gold painted finish, approx. Metal furnace slag can range from glassy to dull and stony in appearance and, when scratched, can range from hard to chalky. Your email address will not be published. Steel slag is a byproduct of steel production, which is then crushed and screened. They started with brown glass, but also produced purple, yellow, green, and blue. Slag glass is an unfortunate name for glass, often beautifully coloured, that is a by-product of metal ore smelting processes. Challinor, Taylor, and Co. also made their own version of this type of glass around the same time. Who apologizes to parents for disobedience in Romeo and Juliet? It was also ground into powder to add to glazes for use in ceramics. Steel slag is the main by-product of steelmaking, and its stacking and burying cause serious pollution to soil and water. Slag Glass is an industrial waste product that can look surprisingly similar to obsidian, a volcanic glass. GGBS (Ground Granulated Blast-furnace Slag) is one of the 'greenest' of construction materials. A good example is steelmaking slag: quicklime (CaO) and magnesite (MgCO3) are introduced for refractory protection, neutralizing the alumina and silica separated from the metal, and assisting in the removal of sulfur and phosphorus from the steel. Another early slag glass was the purple malachite glass by Sowerby, which was sold in the United States under the name "blackberries and cream." Slag glass is a man-made opaque base glass with marbelized swirls in a different color. The light shining through the marbled color creates a really unique effect. A more specific title for this type of glass would be mosaic glass. During the early 20th century, iron ore slag was also ground to a powder and used to make agate glass, also known as slag glass. . United States. If the piece is pink, orange, or red it is not vintage. [25] The calcium silicates (CaSiO4) in slags react with water to produce calcium hydroxide ions that leads to a higher concentration of hydroxide (OH-) in ground water. (817) 251-1668. Ground-granulated blast-furnace slag (GGBS or GGBFS) is obtained by quenching molten iron slag (a by-product of iron and steel-making) from a blast furnace in water or steam, to produce a glassy, granular product that is then dried and ground into a fine powder.Ground-granulated blast furnace slag is a latent hydraulic binder forming calcium silicate hydrates (C-S-H) after contact with water. Sea glass and other treasures from the beaches of southern Spain. Companies continued to make slag glass items well into the mid-20th century. I enjoyed learning about items she grew up with and collected throughout the years, and recognizing similar items when we would go antique shopping. Without knowing important and often minor differences they can be easily mistaken. You can find antique slag lighting fixtures for sale on websites such as Etsy for as low as $20 or as much as $16,000. Depending on where youre from, it may be an insult, a term meaning trash, or, in our case, the waste left over from metal smelting or refining. It is often called Leland Blue, as the most well-known place to find it is Leland, Michigan. Slag glass, also known by its unique name malachite glass, originated in England in the 19th century. Official websites use .gov Two glassmakers in Pennsylvania, Harry Northwood and Thomas Dugan, were the first to imitate slag glass by mixing two colors of glass together and forgoing the actual slag in 1902. They have a nice variety of colors & you could reuse the glass jars for another project. "Meteorites are rarer than gold, platinum, diamonds or emeralds. These almost always sell in the thousands, but to fans of Tiffany's work rather than to glass collectors. Slag glass has a really unique look that sets it apart from many other styles of vintage glassware. Some well-known slag glass manufacturers include Sowerby, Davidson, and Greeners. Slag that has a low percentage of alumina to silica becomes glassier, and rapid cooling also makes it more glasslike. Unlike any other type of glass, slag glass is not transparent. Slag glass producers mark their products with the companys initials or the companys logo. Fenton, Mosser, Boyd Glass, and Summit are some of the common, modern, U.S. manufacturers of slag glass. Secure .gov websites use HTTPS Slag glass was often used in lampshade production as well as for crafting many different types of decorative objects. They bring a sense of the past into a home and they add a pop of color. Doing so would both offset the cost of restoring abandoned mine areas, as well as decrease steel manufacturers current waste footprint. [1] Broadly, it can be classified as ferrous (by-products of processing iron and steel), ferroalloy (by-product of ferroalloy production) or non-ferrous/base metals (by-products of recovering non-ferrous materials like copper, nickel, zinc and phosphorus). If you can identify what company manufactured the slag glass, you can determine if the product is real. 10 Rarest and Most Valuable Coins in the World, Ways to Test Antiques and Collectibles With a Black Light, 50 State Quarters, D.C., and U.S. Kellyco Metal Detectors posted on eBay that it can sell for $300 per gram or more meaning 1 pound could be worth $1 million. Most companies have halted the production of slag glass items altogether. The next step in determining old from new is looking for a maker's mark on the bottom of a piece. Akro Agate is an American company that marked most of their wares ranging from children's dishes to small decorative flower pots. Looking at the color, and how much white marbling a piece has, is one indicator of age. This alkalinity promotes the mineralization of dissolved CO2 (from the atmosphere) to produce calcite (CaCO3), which can accumulate to as thick as 20cm. Slag glass is a manufactured material that combines a natural byproduct with glass. You can determine antique slag glass with a few steps: Slag glass antique items can run anywhere in value from a low of $50 to a high of $1,500. For example, simple things like a bowl sold for around $20 apiece. It's a human-made rock, but it's not a new technique. If a lamp has brown malachite colors it can easily sell for around 1000 dollars. It was primarily blue or green and was formerly chipped away and melted down to make glassware products and jewelry. In some smelting processes, such as ilmenite smelting to produce titanium dioxide, the slag can be the valuable product. This leads to concrete with reduced permeability and better durability. Two vintage brown Sowerby figurines can sell for two completely different processes depending on how the marbling came out. However, ferrous and ferroalloy slags may also have them, which raises concerns about highly weathered slag dumps and upcycled materials. A well-crafted piece of slag glass with the right ratio of additive and correct amount of mixing will strike the perfect balance between looking too chunky and looking too homogenous. There is another theory that slagware, and some other glass decorated with multi-colored enamels, were made up from odds-and-ends of glass left over at the end of the day, Webber reiterates.3, The most common base colors include white, cream, primrose, and blue. Despite its rarity, you can still find slag glass items in modern homes. Identification Tips & History Highlights, One of the most unusual types of antique glass that collectors can investigate, Vaseline glass is absolutely fascinating due to its color, history, and radioactive components. This website uses cookies to improve your experience. True slag glass is marbled and has a variety of bright colors. Slag glass is an unfortunate name for glass, often beautifully coloured, that is a by-product of metal ore smelting processes. A review of steel slag as a substitute for natural aggregate applied to cement concrete. Slag is the collection of compounds that are removed. 12201 Sunrise Valley Drive Reston, VA 20192, Region 2: South Atlantic-Gulf (Includes Puerto Rico and the U.S. Virgin Islands), Region 12: Pacific Islands (American Samoa, Hawaii, Guam, Commonwealth of the Northern Mariana Islands). Newer glass by Fenton, Boyd, and Mosser may also be marked. Popular slag glass lampshades shapes included mushroom, dome and flower petals. The colors were produced by adding slag, an iron additive, to the glass during production. Typically slag glass antiques will be vases, dishes, bowls and decorative figurines and picture frames. Lampshades and chandeliers were commonly produced out of slag glass. Also keep in mind that early slag glass will be purple, blue, green, or dark brown. For todays collectors, slag glass is a greatly sought-after item that can go for a lot of money. These easily sell for thousands when in excellent condition, with Tiffany being the top of the line, of course. The value of slag glass antiques ranges from $20 $20,000. Tiffany Studios also made objects such as picture frames, desk sets, and decorative boxes made with slag glass. Prices go up significantly if a light is signed by a prominent manufacturer like Tiffany Studios or, to a lesser extent, Bradley & Hubbard. The value has generally held steady around $5 for a single cup for a few decades. A mark for Sowerby, Davidson, or Greeners will indicate a vintage U.K. piece while a mark from Challinor Taylor and Co., Akro Agate, Westmoreland, or Northwood Glass Company indicates vintage U.S. glass. Glass manufacturers were thought to have added slag from iron smelting to molten glass. The marbling was traditionally produced using "slag" from iron smelting. Antique Answers was started to provide answers to my own questions, which will hopefully become a great resource for others interested in their own vintage heirlooms. Slag is the byproduct of steel production. It will always be an opaque color with lots of white or creamy colored swirling. However, towards the edge of the streak, the slag may instead be a lighter and creamier version of whatever the base color was since they were more mixed together. Manufacturers experimented with different methods to achieve this malachite-like look. Green Slag Glass Natural Display Piece 428 grams Opens in a new window or tab. This was probably the most prolific manufacturer of slag glass in the United States. Manufacturers used the glass in molds to make bowls, compotes, vases, plant cache pots, and more. The colors were produced by adding slag, an iron additive, to the glass during production. I grew up going to antique stores and markets with my mom and grandmother. Slag glass has something that cannot be found in imperial glass, uranium glass, milk glass, depression glass, carnival glass, or any other type of vintage collectors glassware. As with any glass type, or art in general, different circumstances and people have adopted different names for slag glass. Your email address will not be published. In this case, the slag used for marbling glass is produced when iron is heated during the production process. By clicking Accept All Cookies, you agree to the storing of cookies on your device to enhance site navigation, analyze site usage, and assist in our marketing efforts. [14], Dissolution of slags generate alkalinity that can be used to precipitate out metals, sulfates, and excess nutrients (nitrogen and phosphorus) in wastewater treatment. Not only that, but it can even reduce acids that have built up in soils. Check the bottom or inside of an item for either a name or logo of a manufacturer. Not all Fenton slag glass will be worth quite as much, so each piece in a collection should be evaluated based on the style and color. If the base color is brown, purple, blue, or green theres a decent chance that it is a vintage make. For example, slow cooled BF slags (or air-cooled slags) tend have more crystalline phases than quenched BF slags (ground granulated blast furnace slags) making it denser and better suited as an aggregate. [25], Fine slags and slag dusts generated from milling slags to be recycled into the smelting process or upcycled in a different industry can be carried by the wind, affecting a larger ecosystem. Discerning Victorian consumers resisted purchasing marbleized glass in some cases and preferred more decorative elements in crystal. [5], Slags can serve other purposes, such as assisting in the temperature control of the smelting, and minimizing any re-oxidation of the final liquid metal product before the molten metal is removed from the furnace and used to make solid metal. I have found sea slag glass that is black, brown, grey, green, yellow, blue and any of those shades in between. Instead of taking your glass to the grinder to clean your edges, just run the surface of the stone against the area of your glass that needs smoothing. Slag glass lamps are one of the most sought-after items made of slag glass. Slag glass is a type of opaque pressed glass that includes colorful streaks that create a marbled effect. [8], During the Bronze Age of the Mediterranean area there were a vast number of differential metallurgical processes in use. [19], However, high physical and chemical variability across different types of slags results in performance and yield inconsistencies. For Sale: Single Family home, $550,000, 4 Bd, 2.5 Ba, 1,572 Sqft, $350/Sqft, at 1427 E Dava Dr, Tempe, AZ 85283 This will take a long time, so be prepared to set aside an afternoon. Lighting FixturesPettingell-Andrews Company, c. 1910, Gas and Electric LampsWelsbach Company, c. 1910. [20] Moreover, stoichiometric-based calculation of the carbonation potential can lead to overestimation that can further obfuscate the material's true potential. When looking to purchase real slag glass, look for the marks of the manufacturer. Thus, clinkers are a form of slag. Slag Glass prices range from 50 dollars to 1500 dollars. . Over time, other companies like Imperial Glass, Akro Agate, and Westmoreland began producing and selling their own versions of slag glass. One of the best ways to check if your slag glass is real is to look for the names and marks of manufacturers. Mixing antique pieces with modern amenities is a popular decorating technique.if(typeof ez_ad_units != 'undefined'){ez_ad_units.push([[250,250],'antiqueanswers_com-large-leaderboard-2','ezslot_8',165,'0','0'])};__ez_fad_position('div-gpt-ad-antiqueanswers_com-large-leaderboard-2-0'); Jeannette Glassware, originally Jeannette Bottle Works, was founded in 1888. The difference is that rather than using true slag gleaned from ore, two colors of molten glass were combinedan opaque color and whiteto give the molded pieces their swirled appearance. Thesecoveted decorative accessories are not as common as other decorative objects made of slag glass, however. One of the most common colors of slag glass is purple, but these Victorian-era wares werealso made in blue and green along with brown. Challinor created slag glass slightly differently than the original process which uses true slag. Many antique lamps of these periods were made with stained glass, rather than slag glass, and a careful review of the glass opacity and patterns is necessary to determine the difference. CMoG 79.4.92. 2 Baths. Welcome to Costa Sea Glass, the home of Spanish Sea Glass. Instead of slag, they mixed purple glass with a white-colored glass that did not contain any iron slag. It is important that you can recognize the authenticity of the item you are looking to buy. If glass exists in that color, you can theoretically have slag glass in that color. The major phases of ferrous slag contain calcium-rich olivine-group silicates and melilite-group silicates. You'll find slag glass in blues, browns, and greens as well, though these colors are rarer than the brown/white/cream and purple formulations. What is it called when you wake up during surgery but can't move? It was also ground into powder to add to glazes for use in ceramics. [22], Slags are transported along with slag tailings to "slag dumps," where they are exposed to weathering, with the possibility of leaching of toxic elements and hyperalkaline runoffs into the soil and water, endangering the local ecological communities. The History, Popularity, Value & How To Identify! Have you ever wondered what someone meant by slag glass? Once you find those marks, research the company to see if they are an authentic brand. Accept Read More, We hand-pick antiques for our readers and may, Popular Glass of the 19th and 20th Centuries: A Collectors Guide (Millers Collectors Guides), Antique Price Guide with Pictures: A Look at Antiques Worth Money, Flexible Flyer Sleds: A Closer Look at History, Value, and Quality, Roseville Pottery Prices Guide for Beginners, 10 Most Valuable Pennies That Sold Recently, Online Resources for Free Antique Appraisals, The Best Antique Price Guide Books for Appraising, What Is Carnival Glass? 20 1/2" tall, along with an older metal and reverse glass painted lamp . [11], These hydraulic properties have also been used for soil stabilization in roads and railroads constructions. All Filters; 435.1 g Slag Stone Iron Ore Glass Rock . Slag glass antique lamps sell between $200 and $2,000, and most of the value is in the light itself. Ruby Red LLC is a participant in the Amazon Services LLC Associates Program, an affiliate advertising program designed to provide a means for sites to earn advertising fees by advertising and linking to Amazon.com. She co-founded the Costume Jewelry Collectors International, a global educational website. An avid antiques collector herself, Kate has written about antiques for many years. or Best Offer +$8.95 shipping. ITS MISSING 1 OF THE HANGING TASSLE PIECES ON THE EDGE RIM." Slag glass gets its name from slag, or the byproduct of steel production. Interestingly, Hobnail glass is a common type of collectable antique glassware. [5], In nature, iron, copper, lead, nickel, and other metals are found in impure states called ores, often oxidized and mixed in with silicates of other metals. Mychelle is a writer and web designer who is passionate about a wide variety of topics and enjoys sharing her knowledge with readers. Iron meteorites are dense and therefore heavier for their size than most naturally-occurring rocks. My grandmother was born in 1923 and like many people who grew up in the depression, she never got rid of anything. Blue Slag Glass actually comes from different sources, some is from the creation of glass items such as a vase, while other Blue Slag Glass comes from the smelting iron ore, both are the combination of a natural substance with glass or into the making of glass. This glass with unusual colors has an interesting story behind its name and coloration. Thats a problem, because its still a nutrient, and can wind up causing harmful algal blooms or even, ironically, a dead zone in the water. SOLD FEB 14, 2023. Most antique slag items are brown, blue, green, or purple. Rock wool, a man-made material consisting of natural minerals like basalt or diabase. In many smelting processes, oxides are introduced to control the slag chemistry, assisting in the removal of impurities and protecting the furnace refractory lining from excessive wear. "Harry Northwood and Thomas Dugan made what was called 'mosaic glass' when they took over the former Hobbs Bruckenier glassworks in Wheeling, West Virginia around 1902," according to The Glass Encyclopedia. This antique glass is known by other names including: Brown malachite Brown marble vitro porcelain Mosaic glass Marble glass Variegated glass Image Credit What Is Slag Glass Made Of? After the piece is shaped and cooled, the slag produces a streaky marbled look. Antique Purple and White Slag Glass Cake Stand, Antique EF Industries Green Slag Glass Table Lamp. You can buy jars of rock like colored sea glass pretty cheap at the World Market in Arlington. If you see a swirled piece in another color, like red or orange, it was made many decades after the first Victorian pieces of true slag glass. You can determine the age of a piece of slag by finding the date of production. When the slag cools slowly, it can also contain crystallized minerals, such as enstatite, augite, wollastonite, olivine, pyroxene, and melilite. Glassmakers have achieved a similar-looking marbled effect to slag by simply mixing two different colors of glass together. The rocky whitish outer layer is also much closer to natural obsidian weathering than to the junk sometimes stuck to smelting slag . Slag was often used as a building material, and as railway ballast, among other things, and according to one source, also for sea walls which would explain its presence on beaches. There are three types of slag: ferrous, ferroalloy, non-ferrous slags, which are produced through different smelting processes. 1,572 Sq. Historically, the re-smelting of iron ore slag was common practice, as improved smelting techniques permitted greater iron yieldsin some cases exceeding that which was originally achieved. Some show flow features in the glass and others have flat surfaces from having solidified in a contained space. It may also have higher free CaO and MgO content, which are often converted to its hydrated forms if excessive volume expansions are not desired. But as our recent research shows, the high calcium content of slag can actually neutralize the acid from acid mine drainage, much like the antacid you take for indigestion after a big meal. In this case, the slag is termed synthetic. Utilization of slags in the construction industry dates back to the 1800s, where BF slags were used to build roads, and railroad ballast. The smelting of copper, lead and bauxite in non-ferrous smelting, for instance, is designed to remove the iron and silica that often occurs with those ores, and separates them as iron-silicate-based slags. Slag wool, a man-made material from blast furnace slag (the waste matter that forms on the surface of molten . The ideal thickness of each layer is between 4 to 6 inches.
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