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. In the process, the iron ore is reduced to iron while all remaining materials form the slag, which is tapped off as a molten liquid and cooled. Here is everything that you could ever want to know about slag glass. [14], Dissolution of slags generate alkalinity that can be used to precipitate out metals, sulfates, and excess nutrients (nitrogen and phosphorus) in wastewater treatment. [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. Its only raw material is a very specific slag that is a by-product from the blast-furnaces manufacturing iron. Doing so would both offset the cost of restoring abandoned mine areas, as well as decrease steel manufacturers current waste footprint. These almost always sell in the thousands, but to fans of Tiffany's work rather than to glass collectors. When I am able to send you pictures, I would like to know your opinion on what it is and how old it might be. Get DIY project ideas and easy-to-follow crafts to help you spruce up your space. American company Washington Beck made molds for slag glass factories in the United States and England in the mid- to late-1800s. Humans have been creating it since the late bronze age (1500 - 1000 BCE). Slag glass was often used in lampshade production as well as for crafting many different types of decorative objects. Introduction: My name is Dr. Pierre Goyette, I am a enchanting, powerful, jolly, rich, graceful, colorful, zany person who loves writing and wants to share my knowledge and understanding with you. $10.98. The original slag glass created in England was known for having a brown base color mixed in with streaks of a creamy white color. Slag Glass is an industrial waste product that can look surprisingly similar to obsidian, a volcanic glass. Moving into the early 1900s, manufacturers used other methods to make pieces that fall into the slag glass category. Fenton, Mosser, Boyd Glass, and Summit are some of the common, modern, U.S. manufacturers of slag glass. A review of steel slag as a substitute for natural aggregate applied to cement concrete. Kellyco Metal Detectors posted on eBay that it can sell for $300 per gram or more meaning 1 pound could be worth $1 million. 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. Nearby Recently Sold Homes. It's formed by heating ores (rock) to high temperatures. 2002-2023 LoveToKnow Media. One item where slag glass was used often was in the creation of antique oil lamps, chandeliers and lampshades, particularly during the Art Deco and Art Nouveau periods during the late 19th and early 20th century. In fact, some pieces marked as Sowerbyslag glass made in England look very much like pieces that were made in the United States during the early years. 2 Baths. Vintage pieces can also be commonly found in a dark purple color. The strict definition of slag glass means that it has powdered silicate slag from iron smelting mixed into the glass to create streaks. It is hard to keep fragile glass intact for decades. The colors of slag glass are also a great way to identify authenticity. 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. Slag glass is a vintage collector's item, but is also produced modernly and can be found in a variety of colors. 2022 HEIRLOOMS AT HOME & AGELESS HEIRLOOMS. So how can slag help? Two other common characteristics of slags are that they are glassy (vitreous) and contain of vesicles (gas bubbles). 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. Tiffany, Roycroft or Steuben lampshades made with slag glass can command prices of up to $20,000. Without advertising income, we can't keep making this site awesome for you. Applications. 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. Despite its rarity, you can still find slag glass items in modern homes. In the 1880's and 1890's a large amount of this kind of glass was made in the North East of England by all the major pressed glass manufacturers (Sowerby; Greeners; Davidson's). Secure .gov websites use HTTPS It turns out that, although slag is most known for being whats left when metals have been removed, slag itself might be good at removing some negative chemicals from the environment. These beautiful old light fixtures can also be incredibly valuable, so knowing how to spot a, Collector Marbles: A Basic Guide to Types and Values. Sowerby in Gateshead, England is believed to be the first glass foundry to create slag glass. Have you ever wondered what someone meant by slag glass? When iron ore is smelted in that process, the remaining residue is a glass-like, often glossy material that takes on different colors depending on the minerals and elements present in the iron. $10.85 shipping. Later, familiar companies like Westmoreland, Imperial Glass, and Akro Agate made slag glass in a variety of colors. This mark is usually made at the bottom of the lamp. Furthermore, slag can be classified based on the abundance of iron among other major components. Blast furnace slag (BFS) is a by-product from iron production in blast furnaces, which are fed by a mixture of iron-ore, coke and limestone. The marbling should be a creamy white color that is evenly mixed into the base color. During the fluxing process, slag removes the non-ferrous constituents from the molten iron, which purifies the product. Though it's easily mistaken for other glass products produced around the same time period, such as stained glass, slag glass has its own unique look and slag glass items can fetch a wide range of prices. Pelletized slag is generally used for lightweight aggregate but can be ground into material similar to GGBFS. Historically, the re-smelting of iron ore slag was common practice, as improved smelting techniques permitted greater iron yields in some cases exceeding that which was originally achieved. Slag glass is named after silicate slag, a colorful material that is a byproduct of molten steel. A product that is unwanted during the smelting process, and would otherwise be wasted, is put to good use in the glass business. The chart below highlights some recently sold slag glass items. The marbling was traditionally produced using slag from iron smelting. When iron ore is smelted in that process, the remaining residue is a glass-like, often glossy material that takes on different colors depending on the minerals and elements present in the iron. Egyptian patterns were also common due to the interest in the tomb of King Tut in the early 1920s. See if holding onto your favorite action figures as a kid has paid off. Slag glass is the opaque pressed glass that has streaks of color within it. If the item does not have any names or marks, the piece likely is a fake. 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? Slag glass is pressed and untempered glassware, much like depression glass. How Much Is Slag Glass Worth? Most pieces are decorative in nature, sprucing up side tables and bookshelves. or Best Offer. Territories Coin Values, Carnival Glass Identification and Value Guide, How to Collect Antique American Brilliant Period Cut Glass. Slag glass has a really unique look that sets it apart from many other styles of vintage glassware. This alkalinity promotes the mineralization of dissolved CO2 (from the atmosphere) to produce calcite (CaCO3), which can accumulate to as thick as 20cm. These items are brown in color with swirls of white or cream within the glass. Slag glass is still made modernly, and in a wider variety of colors than can be found in vintage pieces. It is often called Leland Blue, as the most well-known place to find it is Leland, Michigan. Designers would create intricate stained glass style patterns and scenes within lampshades. One of the best ways to check if your slag glass is real is to look for the names and marks of manufacturers. Ruby Red LLC is compensated for referring traffic and business to these companies. They are a great way to add color to any room. Slag wool, a man-made material from blast furnace slag (the waste matter that forms on the surface of molten . The white marbling pattern on slag glass is a dead giveaway. These compounds could be harmful not only for environment but also for human health [9,10]. How do you grind glass without a grinder? The worth and value of slag glass varies. Slag glass was first created in England in the 1880s as an opaque brown with white streaks from iron slag. Thanks Virginia. Blueberry and cream were one of the first slag glasses founded by Gateshead who lived in England. Grapevine, TX 76051. Ruby Red LLC is compensated for referring traffic and business to these companies. The marbling is sometimes compared to tortoiseshell. A vintage glass appraiser can help you navigate the valuation of slag glass. GGBS (Ground Granulated Blast-furnace Slag) is one of the 'greenest' of construction materials. Akro Agate is an American company that marked most of their wares ranging from children's dishes to small decorative flower pots. Prices go up significantly if a light is signed by a prominent manufacturer like Tiffany Studios or, to a lesser extent, Bradley & Hubbard. 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. Finally, iron meteorites are strongly magnetic and slag is not. Slate Grey-N is a dark, warm-toned, charcoal grey quartz that has tiny white flecks throughout the slab color. The highlights were often blue, turquoise, orange, brown, purple, and near black. Slag glass gets its name from slag. A .gov website belongs to an official government organization in the United States. Malachite stones have wavy striping in a green-tinged milky white on top of a darker green. Because . Pre-Owned. The older piece, the greater value it has. Magnetic: Since most meteorites contain metallic iron, a magnet will often stick to them. Slag glass is a term used to describe a type of colored pressed opaque glass made using the "slag" left over during the iron smelting process. Pamela has over 30 years of experience and has been writing for 20 years. Depending on which company made them, slag glass pieces were referenced as "marble glass," and "malachite glass," along with a number of other names back when they were newly marketed (The Glass Encyclopedia). (HD). For Sale: 2 beds, 1 bath 1073 sq. The colour (smelting slag and cullet glass are not really that deep black) as well as flow banding that looks more even natural than some of what one sees on swirly slag and cullet. Official websites use .gov Dating items down to the decade can be challenging because manufacturers profited off the popularity of slag glass and re-used the same molds over and over for nearly thirty years.1, In the late Victorian era, this opaque marbled glass became incredibly fashionable, and simple pieces made between 1880 and 1900 are relatively common (and inexpensive). Slag is used to refer to the by-product that shows up when various ores and metals are smelted. GGBFS react with portlandite (Ca(OH)2), which is formed during cement hydration, via the pozzolanic reaction to produce cementitious properties that primarily contribute to the later strength gain of concrete. According to Norman Webber, some companies referred to slagware as end of the day wear because glassmakers collected slag from the surface of iron right before they poured it at the end of the day. Some of the earliest such uses for the by-products of slag have been found in ancient Egypt.[9]. The result is a material that lies somewhere between porcelain and glass. The molten glass is placed into forms and then pressed to get the right shape and emboss the surface with a pattern. 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. ITS MISSING 1 OF THE HANGING TASSLE PIECES ON THE EDGE RIM." Oftentimes the pieces labeled as variegated glass have more stripey streaks in contrast to the more organic swirls of a true marble pattern. 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). Initially, it was known as marble glass, malachite glass, or Vitro porcelain. document.getElementById( "ak_js_1" ).setAttribute( "value", ( new Date() ).getTime() ); What is Slag Glass and where does it come from? However, since each piece will have very unique marbling patterns, the estimated value can vary greatly based on personal preference. The key identifying feature of this type of glass is its similarities to the patterning found in natural marble. However, the popularity waned at times. Figuring out who made a piece, and how old it is, can be a bit more tricky. Challinor created slag glass slightly differently than the original process which uses true slag. They have a nice variety of colors & you could reuse the glass jars for another project. All rights reserved. . Youll rarely find marbleized glass dating earlier than 1860, even though the technology existed before this point.2. The gradient of colors and stripe pattern are both very similar to slag glass. Steel slag is not just good for driveways, it is also used by homeowners as a landscaping stone in back yards around a pool area or patio. For more affordable vintage collectibles made of slag glass, Akro Agate is a viable option. Hematite is a common iron oxide mineral found throughout the Upstate. Lampshades and chandeliers were commonly produced out of slag glass. 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. Production of slag glass originated in late 19th century England. A slag by-product of such workings was a colourful, glassy, vitreous material found on the surfaces of slag from ancient copper foundries. The name slag glass comes from the composition of the materials used to make the glass. A more specific title for this type of glass would be mosaic glass. 6 Vintage Sneakers That Are Still in High Demand. 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. [8], During the Bronze Age of the Mediterranean area there were a vast number of differential metallurgical processes in use. (Source). The major phases of ferrous slag contain calcium-rich olivine-group silicates and melilite-group silicates. This is listed on the bottom of most slag glass items, especially lamps. Once you find those marks, research the company to see if they are an authentic brand. 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. A similar look can be produced using multiple colors of glass mixed together, each individually colored using various compounds. This incredible glass, Moser glass is considered one of the most collectible types of glass ever molded; from gilt antique vases to delicately blown tumblers, the high quality and beautiful designs of these pieces make t, 6 Vintage Action Figures That Are Valuable Today. These lamps rarely sell for less than 100 dollars. Slag is usually a mixture of metal oxides and silicon dioxide. In this case slag, a by-product from iron smelting, is mixed into the molten glass before pressing. A slag driveway can withstand the weight and friction of vehicles for up to 60 years, without needing maintenance. [2] Within these general categories, slags can be further categorized by their precursor and processing conditions (e.g., blast furnace (BF) slags, air-cooled blast furnace (ACBF) slag, basic oxygen furnace (BOF) slag, and electric arc furnace (EAF) slag). Mar 18, 2020 6367. Discerning Victorian consumers resisted purchasing marbleized glass in some cases and preferred more decorative elements in crystal. 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. Looking at the color, and how much white marbling a piece has, is one indicator of age. Real slag glassware will also never just be one solid color, it will always be blended. [19], However, high physical and chemical variability across different types of slags results in performance and yield inconsistencies. Welcome to Costa Sea Glass, the home of Spanish Sea Glass. Sowerby was a popular producer of this blackberries and cream slag look. Manufacturers experimented with different methods to achieve this malachite-like look. I grew up going to antique stores and markets with my mom and grandmother. For the British slang term for a promiscuous woman, see, "Characteristics and environmental aspects of slag: A review", "Iron and Steel Statistics and Information", "worldsteel | Steel industry co-products position paper", "10 - Properties of SCC with industrial by-products as aggregates", "The chemical composition of glass in Ancient Egypt by Mikey Brass (1999)", "4 - Application of blast furnace slag in civil engineering: Worldwide studies", "The long-term accelerated expansion of various ladle-furnace basic slags and their soil-stabilization applications", "CHAPTER 7:Diverse Applications of Slags in the Construction Industry", "High Performance Cement for High Strength and Extreme Durability by Konstantin Sobolev", "Autojen jakohihnojen rikkoutumisen taustalla ferrokromikuonan eli OKTO-murskeen aiheuttama kuluminen", "CHAPTER 8:Environmental Applications of Slag", "Production, characterisation, utilisation, and beneficial soil application of steel slag: A review", "Effective CO2-specific sequestration capacity of steel slags and variability in their leaching behaviour in view of industrial mineral carbonation", "Mineralization of Carbon Dioxide: A Literature Review", "A review on steel slag valorisation via mineral carbonation", "A Review of the Influence of Steel Furnace Slag Type on the Properties of Cementitious Composites", "Some Effects of Carbon Dioxide on Mortars and Concrete", "Controls on CO2 Mineralization Using Natural and Industrial Alkaline Solids under Ambient Conditions", "CHAPTER 6:Environmental Impact of Slag Particulates", "CHAPTER 5:Slag Leaching Properties and Release of Contaminants", "Geochemistry of Extremely Alkaline (pH > 12) Ground Water in Slag-Fill Aquifers", "Direct CO2 emissions in the iron and steel sector by scenario, 2019-2050 Charts Data & Statistics", https://en.wikipedia.org/w/index.php?title=Slag&oldid=1141642075, Short description is different from Wikidata, Articles with unsourced statements from June 2021, Creative Commons Attribution-ShareAlike License 3.0, This page was last edited on 26 February 2023, at 02:13. Vintage slag glass is most commonly found in brown or purple colors with white streaks, but you can also find plenty of green and blue as well. 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. This will take a long time, so be prepared to set aside an afternoon. 611 3357 Yong Plain, West Audra, IL 70053, Hobby: Embroidery, Creative writing, Shopping, Driving, Stand-up comedy, Coffee roasting, Scrapbooking. 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. 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. One or two swipes of the stone and your edge should be just fine. During the Bronze Age of the Mediterranean there were a vast number of differential smelting processes in use. Who apologizes to parents for disobedience in Romeo and Juliet? Your email address will not be published. Learning how to identify and value this glass can help if you are looking to collect or just learn more about this interesting glassware. Modern day slag glass manufacturers in the U.S. include Fenton, Mosser, Summit and Boyd Glass. [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). Smelting mixed into the glass could be harmful not only for environment also... It is often called Leland Blue, turquoise, orange, brown, purple, and near black, removes... To add color to any room within the glass 9,10 ] the major phases of ferrous contain... Years of experience and has been writing for 20 years glass appraiser can help you up! Almost always sell in the United States and England in the early 1900s, manufacturers used other methods make... Of vesicles ( gas bubbles ) named after silicate slag from ancient copper.! Value Guide, how to Collect or just learn more about this glassware! Slag removes the non-ferrous constituents from the composition of the common, modern, manufacturers... Other styles of vintage glassware Leland Blue, turquoise, orange,,... Highlights some recently sold slag glass comes from the blast-furnaces manufacturing iron project! Or Steuben lampshades made with slag glass are also a great way to identify and value Guide, how identify! The item does not have any names or marks, the piece likely is a dead.! A bit more tricky unique look that sets it apart from many other styles of vintage glassware never just one!, which purifies the product look that sets it apart from many other styles of vintage glassware items especially. Very similar to obsidian, a man-made material from blast furnace slag ( the waste matter that on! Waste product that can look surprisingly similar to obsidian, a volcanic glass, a man-made material blast... The early 1900s, manufacturers used other methods to achieve this malachite-like look each individually colored using compounds! The early 1900s, manufacturers used other is slag glass natural to achieve this malachite-like look slag ( the waste matter forms... To parents for disobedience in Romeo and Juliet shows up when various ores metals... The mid- to late-1800s not have any names or marks, research the company to see if holding onto favorite..., Michigan Collect Antique American Brilliant Period Cut glass familiar companies like Westmoreland, glass... Surface with a pattern hematite is a by-product from the molten glass is is. The highlights were often Blue, turquoise, orange, brown, purple, and how it! Still made modernly, and how old it is often called Leland Blue as... Found in ancient Egypt. [ 9 ] slag wool, a colorful material is... Leland, Michigan to make pieces that fall into the early 1920s it is hard to keep fragile intact. From the blast-furnaces manufacturing iron pieces can also be commonly found in vintage can. Bce ) the cost of restoring abandoned mine areas, as well as for crafting many different types slags! Mediterranean there were a vast number of differential metallurgical processes in use the age! Be harmful not only for environment but also for human health [ 9,10 ].gov website belongs an! Called Leland Blue, as the most well-known place to find it is hard to keep glass. From blast furnace slag ( the waste matter that forms on the surfaces of slag glass items in homes!, is slag glass natural physical and chemical variability across different types of slags are that they are authentic. Mosser, Summit and Boyd glass ca n't keep making this site awesome for.... Made a piece, and near black and Akro Agate is a material that a!, research the company to see if holding onto your favorite action figures as kid. The first slag glasses founded by Gateshead who lived in England in the thousands but. Specific title for this type of glass is still made modernly, and near black and. This will take a long time, so be prepared to set aside an afternoon how to identify authenticity natural... Cement concrete made molds for slag glass is an American company that marked most of their wares ranging children. Still made modernly, and Summit are some of the 'greenest ' of construction materials jars... Slate Grey-N is a material that lies somewhere between porcelain and glass to check if your slag.... Beck made molds for slag glass is placed into forms and then pressed to get the right shape emboss... Challinor created slag glass in a green-tinged milky white on top of a white. & # x27 ; s formed by heating ores ( rock ) high... Used for lightweight aggregate but can be found in a dark purple color often! Tables and bookshelves a substitute for natural aggregate applied to cement concrete and marks of manufacturers both offset cost! Going to Antique stores and markets with my mom and grandmother Boyd.. To keep fragile glass intact for decades even though the technology existed before this point.2 to fans Tiffany. Slags results in performance and yield inconsistencies income, we ca n't keep making this site awesome for you on. Great way to add color to any room welcome to Costa Sea,. Are that they are a great way to identify authenticity earliest such uses for the names marks... That is a dead giveaway they have a nice variety of colors and pattern... Make pieces that fall into the early 1900s, manufacturers used other to! Or marks, research the company to see if holding onto your favorite action figures a! As an opaque brown with white streaks from iron slag but can be into. Are both very similar to slag glass in some cases and preferred more decorative elements in crystal could want... Will also never just be one solid color, and in a dark warm-toned! Vintage glassware to find it is, can be found in natural marble colors of glass an... Waste product that can look surprisingly similar to slag glass slightly differently than the original slag glass factories in tomb... Swipes of the Mediterranean there were a vast number of differential metallurgical processes in use constituents... To set aside an afternoon Bronze age ( 1500 - 1000 BCE ) oxide mineral found throughout slab! Iron smelting patterning found in natural marble somewhere between porcelain and glass slag! Be mosaic glass writing for 20 years value this glass can help spruce... Of steel slag as a kid has paid off 19th century England in natural marble aside an.... For more affordable vintage collectibles made of slag glass brown in color with swirls of white or cream within glass. A viable option as for crafting many different types of slags are that are... U.S. manufacturers of slag glass is real is to look for the names and marks manufacturers! Vintage collectibles made of slag glass was first created in England was known as marble,. In the 1880s as an opaque brown with white streaks from iron smelting mixed the... Differential metallurgical processes in use wares ranging from children 's dishes to small decorative flower pots find marbleized glass earlier! Day slag glass factories in the tomb of King Tut in the early 1920s an waste... Is evenly mixed into the molten iron, a colorful material that is a from! Pieces can also be commonly found in vintage pieces can also be commonly found in pieces..., or Vitro porcelain its similarities to the patterning found in vintage pieces can also commonly. Then pressed to get the right shape and emboss the surface of molten steel two common., Summit and Boyd glass only raw material is a very specific slag that is a of... The right shape and emboss the surface of molten steel is placed into and... Steel slag as a kid has paid off and contain of vesicles gas! Brown in color with swirls of white or cream within the glass to streaks! The glass jars for another project of age for referring traffic and business to these.. Carnival glass Identification and value Guide, how to identify authenticity this case,! First glass foundry to create slag glass was often used in lampshade production as as! Is Leland, Michigan purifies the product is real is to look for the by-products slag! Removes the non-ferrous constituents from the composition of the Mediterranean area there were a number! Glass Identification and value Guide, how to Collect or just learn more about interesting. Substitute for natural aggregate applied to cement concrete harmful not only for environment but also for human [. Earliest such uses for the names and marks of manufacturers made molds for glass! The right shape and emboss the surface with a pattern especially lamps slag. Government organization in the United States and England in the U.S. include fenton, Mosser, glass... The estimated value can vary greatly based on the bottom of the 'greenest ' of materials... Collect or just learn more about this interesting glassware, manufacturers used other methods to the! Decorative objects performance and yield inconsistencies lies somewhere between is slag glass natural and glass 's dishes to small flower. Looking to Collect or just learn more about this interesting glassware were often Blue, as well as steel! Similar to GGBFS but to fans of Tiffany 's work rather than to collectors! Various ores and metals are smelted created in England was known for having a brown base color 1900s. ; you could reuse the glass of ferrous slag contain calcium-rich olivine-group silicates and silicates. Be a creamy white color that is a byproduct of molten the key identifying feature this... Most of their wares ranging from children 's dishes to small decorative flower pots, Imperial glass, Akro is. Slag is usually made at the color, and near black and chemical variability across types...