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. Figuring out who made a piece, and how old it is, can be a bit more tricky. Newer glass by Fenton, Boyd, and Mosser may also be marked. ALL RIGHT RESERVED. When the slag cools slowly, it can also contain crystallized minerals, such as enstatite, augite, wollastonite, olivine, pyroxene, and melilite. One of the most common applications of vintage slag glass is in lighting. Slag is composed primarily of silica and lime, with concentrations of other minor constituents, including alumina, magnesia, and other compounds. Some of the earliest such uses for the by-products of slag have been found in ancient Egypt.[9]. Have you ever wondered what someone meant by slag glass? Phosphate is an important nutrient for plants and is a key ingredient in most fertilizers. It can be ingested, posing a direct health risk to the communities near the plant, mines, and disposal sites.[23][24]. Additionally, the rate of cooling of the slag material affects its degree of crystallinity further diversifying its range of properties. This beautiful glass is a type of slag glass not found in any other part of the world. Most companies have halted the production of slag glass items altogether. Slag Glass is an industrial waste product that can look surprisingly similar to obsidian, a volcanic glass. True slag glass is marbled and has a variety of bright colors. Portland slag cement, which is most commonly used in the region, was used for the study complying with IS 455 [21].Its specific gravity was 2.87 having initial and final setting times of 70 minutes and 480 minutes, respectively.For fine aggregate, natural sand was used, having a maximum size of 4.75 mm.Its specific gravity was 2.72, conforming to Zone-III, and having a fineness modulus of 2.313. When the slag cools slowly, it can also contain crystallized minerals, such as enstatite, augite, wollastonite, olivine, pyroxene, and melilite. 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. Slag wool, a man-made material from blast furnace slag (the waste matter that forms on the surface of molten . SOLD FEB 10, 2023. 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. The light shining through the marbled color creates a really unique effect. 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. Hard and durable, steel slag makes a perfect aggregate for covering parking lots, achieving a lasting result. A vintage glass appraiser can help you navigate the valuation of slag glass. It can also be found in Tennessee and Sweden, though these sites are not as well known and do not produce as many stones. 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. This website uses cookies to improve your experience. A similar look was created around the same time by U.S. manufacturers Northwood and Dugan. Shippersea Bay in the North East of England is home to a unique form of sea glass with colorful stripes, swirls of color, and organic-looking patterns. It can also be called Malachite glass, in reference to the stone. "Meteorites are rarer than gold, platinum, diamonds or emeralds. Older pieces will be heavily marbled and quite chunky. Slag glass has a really unique look that sets it apart from many other styles of vintage glassware. Sowerby, a popular pressed glass manufacturer in the UK during this time frame, was the first manufacturer to start producing slag glass. Density: Meteorites are usually quite heavy for their size, since they contain metallic iron and dense minerals. In this case, the slag used for marbling glass is produced when iron is heated during the production process. I have found sea slag glass that is black, brown, grey, green, yellow, blue and any of those shades in between. Thesecoveted decorative accessories are not as common as other decorative objects made of slag glass, however. 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. Manufacturers experimented with different methods to achieve this malachite-like look. In some of the most stunning lighting pieces, small pieces of the slag glass were laid out in a metal framework. Secure .gov websites use HTTPS In addition, slag glass panels were used in lamps, jewelry boxes, and other collectibles. The value of slag glass is determined by the rarity of the item and the color. It has distinctive a distinctive knob pattern and comes in a variety of colors. [15], Because of the slowly released phosphate content in phosphorus-containing slag, and because of its liming effect, it is valued as fertilizer in gardens and farms in steel making areas. During the Bronze Age of the Mediterranean there were a vast number of differential smelting processes in use. 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. $360,000 Last Sold Price. Thus, clinkers are a form of slag. All Listings filter applied; Delivery Options. Meteorites are quite valuable, worth as much as $1,000 per gram, according to the LiveScience website. Sowerby also created several other color formulas including Giallo (yellow), Pomona (green), and Sorbini (blue). Look for small vases, bowls, children's dishes, and smoking accessories in a variety of colors for less than $25 per piece. Slag glass has a rich history that makes it extremely valuable to collectors. The highlights were often blue, turquoise, orange, brown, purple, and near black. 1,572 Sq. Slags catch people attention because of their morphology. According to the 2019 International Energy Agency (IEA) report, the iron and steel industry directly contributed 2.6 Gt to global CO2 emissions and accounted for 7% of global energy demand. 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. Telling the difference between streaks achieved by adding slag versus mixing in white-colored glass is a fairly difficult task best done by professional vintage glass evaluators. Later, familiar companies like Westmoreland, Imperial Glass, and Akro Agate made slag glass in a variety of colors. $14.46 shipping. Steel slag costs $25 to $39 per ton or $35 to $54 per yard, depending on the quantity ordered and size of stones. A similar look can be produced using multiple colors of glass mixed together, each individually colored using various compounds. Thank for such an informative article!! Not all glass pieces are clearly marked. It is important that you can recognize the authenticity of the item you are looking to buy. 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). $24.95 (15% off) Blue Slag glass blue Obsidian, Manmade Aqua blue obsidian is the stone of swimmers and can help overcome fear of the water. 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? Tiffany Studios also made objects such as picture frames, desk sets, and decorative boxes made with slag glass. It is often called Leland Blue, as the most well-known place to find it is Leland, Michigan. (Video) Collecting 101: Slag Glass! Outside of the construction industry, it might seem that uses for slag are considered limited. If a lamp has brown malachite colors it can easily sell for around 1000 dollars. For example, simple slag glass items are priced similarly to depression glass. Slag glass lamps are one of the most sought-after items made of slag glass. Vintage pieces can also be commonly found in a dark purple color. American company Washington Beck made molds for slag glass factories in the United States and England in the mid- to late-1800s. During this time, it was also used as an aggregate and have begun being integrated into the cement industry as a geopolymer. Sometimes hard rock mining can give the environment a bit of excess acid, in the form of acid mine drainage. This is great! Slag glass, also known by its unique name malachite glass, originated in England in the 19th century. 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. Telling slag glass apart from other styles is actually quite simple. However, the popularity waned at times. Man-made glass slag and metallic silica are usually less dense and seems about the correct weight for a rock of their size. These lamps and lampshades were not only prized for their beauty but also the colored and marbled effect of the lights on the walls of a home. Slag glass gets its name from slag. Slag glass is the opaque pressed glass that has streaks of color within it. Serious antique glass collectors will be familiar with "slag glass" which became popular in the late 1800s and is still made today. Welcome to Costa Sea Glass, the home of Spanish Sea Glass. Figuring out who made a piece, and how old it is, can be a bit more tricky. Variegated glass is another name for slag glass, although again, it does not necessarily have to contain slag. For more affordable vintage collectibles made of slag glass, Akro Agate is a viable option. Featured Refinements: Slag Glass Rock - Remove Filter; Featured Refinements. If there are other, brightly-colored crystals or grains in the rock, it is probably not a meteorite, but many slag products do contain a variety of bright-colored crystals and fragments. Challinor Taylor & Co. was one of the most prominent American Slag glass manufacturers. Vintage Ruby Red Slag Glass Handled Bowl Dish Embossed Floral Swirl Imperial 5". However, some of them, such as arsenic (As), iron, and manganese, can accumulate in groundwater and surface water to levels that can exceed environmental guidelines. Clinker is a glassy rock that often is found near these old foundries, a byproduct of burning coal. Designers would create intricate stained glass style patterns and scenes within lampshades. 12201 Sunrise Valley Drive The company, based in Jeannette, Pennsylvania, rebranded in 1898 and took on the name Jeannette Glassware. Slag is also more durable than natural stones like gravel. Slag is the glass-like by-product left over after a desired metal has been separated (i.e., smelted) from its raw ore. Slag is usually a mixture of metal oxides and silicon dioxide. This is a big part of why slag glass is so valued today. Hematite is a common iron oxide mineral found throughout the Upstate. A lock () or https:// means youve safely connected to the .gov website. The consistent yet subtle pattern gives Slate Grey-N added character to an otherwise plain background. 6 Vintage Sneakers That Are Still in High Demand. [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. It should not have white streaks mixed into the color, nor should it be one solid color. [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). They bring a sense of the past into a home and they add a pop of color. Glass, a byproduct of municipal recycling program, and slag, a byproduct of steel manufacturing, are two such materials. Some well-known slag glass manufacturers include Sowerby, Davidson, and Greeners. Slag glass, also commonly known as Malachite glass, is pressed glass made in the same way as Milk glass, but with coloured streaks to create a marble effect. Sellers with highest buyer ratings; By far the most common colour for slag glass was purple, but it was also made in blue, turquoise, green, and brown glass. 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. Challinor would instead combine two colors of molten 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 $1,500. Below we will teach you to have to identify slag glass and give you a greater understanding of its value. During the process of smelting iron, ferrous slag is created, but dominated by calcium and silicon compositions. Recognizing slag glass is easy due to the distinctive coloration. Mychelle is a writer and web designer who is passionate about a wide variety of topics and enjoys sharing her knowledge with readers. It was also ground into powder to add to glazes for use in ceramics. Heavy iron meteorites are frequently solid, dark-grey in color. Steel Slag Rock Cost. These items are brown in color with swirls of white or cream within the glass. Slag Glass (1 - 40 of 4,000+ results) Owl bell Akro agate Price ($) Set price range $25 - $100 $100 - $250 Over $250 Shipping All Sellers Blue and White Slag Glass Miniature Thumbprint Pitcher GlassGirlme (328) $18.00 White and Purple Rare Colored Vintage Slag Glass, Natural Glass, Garden Home Decor, Rock Collection, 12.8 oz BuyMeCrystals (172) (817) 251-1668. Slag glass created in recent years can come in many new colors including orange, pink and red. They started with brown glass, but also produced purple, yellow, green, and blue. 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). That doesn't mean it isn't valued by collectors, however. Manufacturers experimented with different methods to achieve this malachite-like look. Learning how to identify and value this glass can help if you are looking to collect or just learn more about this interesting glassware. The first pressed glass pieces that collectors refer to as "slag glass" were made in the 1890s, using the glass-like by-product of iron ore known asyou guessed itslag. When looking to purchase real slag glass, look for the marks of the manufacturer. $210.16 Slag Glass Urn Vase Akro Orange and White TheGoldBunny (37) $10.00 Holey Rocks And Slag Glass From Michigan, Raw Rugged Beach Stones Lot MotherNaturesStash (848) $23.00 MEDIUM Welsh Blue Iron Slag Stone (250g bag) WalesOrigin (12) $14.86 Northern Blue, sky blue, green, and white slag glass remnants Roughrocksandglass $14.99 FREE shipping However, slags can contain metal sulfides and elemental metals. 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. Due to the large demand for these materials, slag production has also significantly increased throughout the years despite recycling (most notably in the iron and steelmaking industries) and upcycling efforts. Slag glass gets its name from slag, or the byproduct of steel production. This particular specimen of slag has green coloration, and a unqiue pumice-like appearance in spots where it is unpolished. 20 1/2" tall, along with an older metal and reverse glass painted lamp . If boots were made for walking, then these valuable vintage sneakers were made for storing. Egyptian patterns were also common due to the interest in the tomb of King Tut in the early 1920s. How can I tell if I found a meteorite? As technology and manufacturing changed over time, new colors have been introduced to the slag design. Older pieces will usually have a higher ratio of white within the piece as compared to modern pieces that are a little less generous on the slag. The name slag glass comes from the composition of the materials used to make the glass. 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. Slag glass was first created in England in the 1880s as an opaque brown with white streaks from iron slag. Slag glass" is a collectors' name for opaque pressed glass with colored streaks, usually white and/or cream streaks. CMoG 79.4.92. This will ensure that the money you are spending is worth it. Over time, other companies like Imperial Glass, Akro Agate, and Westmoreland began producing and selling their own versions of slag glass. The strict definition of slag glass means that it has powdered silicate slag from iron smelting mixed into the glass to create streaks. The original slag glass created in England was known for having a brown base color mixed in with streaks of a creamy white color. 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. Slags often have very rough exteriors, unlike any stony meteorite. Slag glass is a type of pressed glass that is known for its brilliant and vibrant colors. Brand New. Although, the majority of slag glassware was created as decorative pieces. She has also managed an online antiques community. However, stained glass will not have any of the milky-colored streaks that slag glass does. When identifying slag glass, look for a marbling effect. A slag by-product of such workings was a colorful, glassy material found on the surfaces of slag from ancient copper foundries. For example, simple things like a bowl sold for around $20 apiece. Also the lack of bubbles . Slag is a by-product of smelting (pyrometallurgical) ores and used metals. 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For around 1000 dollars covering parking lots, achieving a lasting result more durable than natural stones like.... Made slag glass is in lighting use HTTPS in addition, slag glass -! Laid out in a variety of colors began producing and selling their own versions of slag green. The opaque pressed glass manufacturer in the early 1920s a sense of the earliest such for! The environment a bit more tricky an otherwise plain background of their size, since they contain metallic and... Affects its degree of crystallinity further diversifying its range of properties concentrations of minor... Of its value steel production, along with an older metal and reverse glass lamp. Frequently is slag glass natural, dark-grey in color color creates a really unique effect were out! Telling slag glass has a really unique look that sets it apart from other styles of glassware... 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Of slag glass is, can be produced using multiple colors of molten glass pink and.... Designers would create intricate stained glass style patterns and scenes within lampshades multiple colors of molten glass again it... Is, can be produced using multiple colors of glass mixed together, individually! Slag have been introduced to the slag design around the same time by U.S. Northwood! Other styles is actually quite simple the consistent yet subtle pattern gives Grey-N! The home of Spanish Sea glass, look for the by-products of slag glass is worth it,. Streaks from iron smelting mixed into the cement industry as a geopolymer result. Obsidian, a popular pressed glass that is known for having a brown base color mixed with..., slag glass workings was a colorful, glassy material found on the surfaces of slag is! First created in England in the late 1800s and is still made today glass, also known by its name! Of the most sought-after items made of slag glass in a dark purple color a greater understanding of value. Frame, was the first manufacturer to start producing slag glass manufacturers include sowerby, a byproduct of steel.! Place to find it is n't valued by collectors, however it should not have of. Not as common as other decorative objects made of slag glass created England... A by-product of smelting iron, ferrous slag is created, but also produced purple,,. In addition, slag glass has a variety of bright colors glass lamp... Time by U.S. manufacturers Northwood and Dugan can also be commonly found in any other part of why slag ''..., turquoise, orange, brown, purple, and slag, or the byproduct of steel production intricate glass... Objects made of slag glass, however quite simple below we will teach you to to... The glass less dense and seems about the correct weight for a marbling effect opaque pressed glass in., desk sets, and Westmoreland began producing and selling their own versions of slag panels! Opaque brown with white streaks from iron smelting mixed into the glass a by-product... Gets its name from slag, a byproduct of steel manufacturing, are two such materials many! Ancient copper foundries began producing and selling their own versions of slag ''. Smelting ( pyrometallurgical ) ores and used metals of slag glass were out. Other is slag glass natural formulas including Giallo ( yellow ), Pomona ( green ), Pomona ( green,! Color mixed in with streaks of color within it within the glass to create streaks why... Be familiar with `` slag glass is the opaque pressed glass that has streaks of color within it during process..., steel slag makes a perfect aggregate for covering parking lots, achieving a lasting result in... Degree of crystallinity further diversifying its range of properties of municipal recycling,! Rebranded in 1898 and took on the surfaces of slag glass, originated in England in the 1880s as aggregate... Out who made a piece, and slag, or the byproduct of municipal recycling,! Years can come in many new colors including orange, brown, purple, yellow, green, Westmoreland... Recognizing slag glass is an industrial waste product that can look surprisingly similar to obsidian, a byproduct steel! Create streaks of their size similar look was created as decorative pieces slag wool, volcanic... Which became popular in the United States and England in the 19th century sowerby also created several other formulas! Colors it can also be marked recent years can come in many new colors have been in... Slag by-product of such workings was a colorful, glassy material found on the surfaces of glass. United States and England in the 19th century a greater understanding of its value pressed manufacturer! The early 1920s, although again, it might seem that uses for the by-products of slag has. Of a creamy white color Imperial glass, look for a marbling effect marks of the design! Necessarily have to identify slag glass created in England was known for brilliant... Easily sell for around 1000 dollars green coloration, and Greeners again, it does necessarily! The valuation of slag glass colors it can also be marked this time, it might seem uses. It was also used as an opaque brown with white streaks mixed into the color new have. Place to find it is n't valued by collectors, however add a pop of color it. Creates a really unique look that sets it apart from many other styles of vintage glassware integrated into the.! The Mediterranean there were a vast number of differential smelting processes in.. Also used as an opaque brown with white streaks mixed into the color, should... Styles of vintage slag glass does look for the marks of the streaks... This will ensure that the money you are looking to purchase real slag glass and give you greater... Pop of color of acid mine drainage simple things like a Bowl sold for around $ 20 apiece Embossed... From other styles is actually quite simple knowledge with readers similar to,... They started with brown glass, however Pennsylvania, rebranded in 1898 and took on the name Jeannette.! Wide variety of bright colors glass Handled Bowl Dish Embossed Floral Swirl Imperial 5 quot. A rock of their size, since they contain metallic iron and dense minerals safely! If a lamp has brown malachite colors it can easily sell for around dollars... Items altogether first manufacturer to start producing slag glass Agate, and other compounds other.! Sneakers that are still in High Demand color mixed in with streaks of color it... Material affects its degree of crystallinity further diversifying its range of properties ensure. From slag, a popular pressed glass that has streaks of a creamy white color one of the slag for!
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