Slag glass, also known by its unique name malachite glass, originated in England in the 19th century. A similar look can be produced using multiple colors of glass mixed together, each individually colored using various compounds. 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. They're easy to find, and make a colorful, decorative display in your home, offi, If you're hoping to add some historic charm to your home, antique chandeliers can be a wonderful choice. Slag glass is commonly found in purple, less common in blue and brown and green. It can also be called Malachite glass, in reference to the stone. [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). CMoG 79.4.92. . The ideal thickness of each layer is between 4 to 6 inches. Slag Glass is an industrial waste product that can look surprisingly similar to obsidian, a volcanic glass. My grandmother was born in 1923 and like many people who grew up in the depression, she never got rid of anything. Some of the earliest such uses for the by-products of slag have been found in ancient Egypt.[9]. Work with a qualified appraiser to help you identify the manufacturer and type of slag glass antiques you have, including antique glass insulators, to determine the true market value. During this time, it was also used as an aggregate and have begun being integrated into the cement industry as a geopolymer. Milk glass typically comes in white, blue, green, pink, black, yellow, and brown. This wouldnt be considered slag glass in the strict traditional definition, but many collectors will still use the term to refer to any marbled, opaque, pressed glass pieces. 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. Malachite stones have wavy striping in a green-tinged milky white on top of a darker green. I have found sea slag glass that is black, brown, grey, green, yellow, blue and any of those shades in between. Eventually, it became known as slagware or slag glass. Antique Glass Insulators and Their Electrifying History, Antique glass insulators are a low cost but very popular collectible that come in a myriad of fun shapes and colors. Most manufacturers use up tp 40% to 60% recycled glass content. What does Capulet do when Juliet apologizes? 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. This leads to concrete with reduced permeability and better durability. Also the lack of bubbles . Marble or marbled glass was another name for slag glass since the resulting glass ware . 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. 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. Look for small vases, bowls, children's dishes, and smoking accessories in a variety of colors for less than $25 per piece. The value of slag glass items can also be determined by the condition of the item. All Listings filter applied; Delivery Options. Thank for such an informative article!! Challinor Taylor and Co. was an early U.S. producer of slag glass and created slag glassware in higher quantities than most other glass manufacturers. If the piece is pink, orange, or red it is not vintage. Moving into the early 1900s, manufacturers used other methods to make pieces that fall into the slag glass category. Real slag glass will not have a solid color but rather a blended, marble look. Discerning Victorian consumers resisted purchasing marbleized glass in some cases and preferred more decorative elements in crystal. The key identifying feature of this type of glass is its similarities to the patterning found in natural marble. or Best Offer +$8.95 shipping. Slate Grey-N is a dark, warm-toned, charcoal grey quartz that has tiny white flecks throughout the slab color. 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. An Identification Guide for Beginners, Vases, Compote, Creamer, and Bowls, Lot of 7. Faurit is a website that writes about many topics of interest to you, a blog that shares knowledge and insights useful to everyone in many fields. As molten iron cools, a silicate slag forms on top of it. [6] To flux the silica produced during steelmaking, limestone and/or dolomite are added, as well as other types of slag conditioners such as calcium aluminate or fluorspar. Get DIY project ideas and easy-to-follow crafts to help you spruce up your space. Interestingly, Hobnail glass is a common type of collectable antique glassware. True slag glass is marbled and has a variety of bright colors. This created the marbled effect and bright variations in color that make slag glass so unique. (Source). The pieces produced are of a very similar style and quality, and it can be difficult to identify exactly where a vintage piece was originally produced. 701 South Main Street, #103. 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. 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. How to Cut Hand Rolled Art Glass | Delphi Glass - YouTube. 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. 10.2.2 Blast furnace slag. How do you grind glass without a grinder? ALL RIGHT RESERVED. However, slags can contain metal sulfides and elemental metals. The older piece, the greater value it has. Oftentimes the pieces labeled as variegated glass have more stripey streaks in contrast to the more organic swirls of a true marble pattern. The acid then dissolves other metals and can contaminate drinking water, disrupt the growth and reproduction of aquatic plants and animals, and even corrode parts of infrastructures such as bridges. The colors were produced by adding slag, an iron additive, to the glass during production. Other manufacturers quickly caught on and the style rose in popularity soon following its creation. This would still give the marble effect without the use of actual slag. Thesecoveted decorative accessories are not as common as other decorative objects made of slag glass, however. As technology and manufacturing changed over time, new colors have been introduced to the slag design. 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). Parsons' studies identify dissolution of the glassy material in the slag as the major source of potentially toxic metals released to the environment. Slag usually refers to a glassy by-product of smelting ores to retrieve the metal. A similar look was created around the same time by U.S. manufacturers Northwood and Dugan. If glass exists in that color, you can theoretically have slag glass in that color. Slag glass has a really unique look that sets it apart from many other styles of vintage glassware. [21] To this end, some have proposed performing a series of experiments testing the reactivity of a specific slag material (i.e., dissolution) or utilizing the topological constraint theory (TCT) to account for its complex chemical network. Egyptian patterns were also common due to the interest in the tomb of King Tut in the early 1920s. Most styles of vintage glassware have a plethora of names that they go by, and slag glass is no different. Thanks Virginia. Blueberry and cream were one of the first slag glasses founded by Gateshead who lived in England. $86.99. 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. Slag glass is a manufactured material that combines a natural byproduct with glass. As a co-product of steelmaking, slag is typically produced either through the blast furnace - oxygen converter route or the electric arc furnace - ladle furnace route. However, since each piece will have very unique marbling patterns, the estimated value can vary greatly based on personal preference. This particular specimen of slag has green coloration, and a unqiue pumice-like appearance in spots where it is unpolished. I'm Stacy Jones and I love antiques! During the fluxing process, slag removes the non-ferrous constituents from the molten iron, which purifies the product. Here's an example of a Radium-painted watch hand in a cloud chamber. I grew up going to antique stores and markets with my mom and grandmother. Territories Coin Values, Carnival Glass Identification and Value Guide, How to Collect Antique American Brilliant Period Cut Glass. 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. I enjoyed learning about items she grew up with and collected throughout the years, and recognizing similar items when we would go antique shopping. 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. See if holding onto your favorite action figures as a kid has paid off. The marbled effect is gorgeous on its own, but shining light through a complicated and colorful design is even more stunning. Slag glass is an unfortunate name for glass, often beautifully coloured, that is a by-product of metal ore smelting processes. Now, you can find slag glass pieces in practically any color. A .gov website belongs to an official government organization in the United States. Similarly, ferrous slags have been used as soil conditioners to rebalance soil pH and fertilizers as sources of calcium and magnesium. I use the term here to also include any man-made, rock-like by-product of heating things to high temperature. These include items ranging from small figurines to larger bowls made of red glass several decades ago, so they are collectible but not yet antique. [10], Today, ground granulated blast furnace slags (GGBFS) are used in combination with Portland cement (PC) to create "slag cement." Magnetic: Since most meteorites contain metallic iron, a magnet will often stick to them. The mark will usually be somewhere inconspicuous and be printed fairly small. 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. Prices go up significantly if a light is signed by a prominent manufacturer like Tiffany Studios or, to a lesser extent, Bradley & Hubbard. United States. 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). Slag glass created in recent years can come in many new colors including orange, pink and red. Blue slag is a man-made rock created as a by-product of iron smelting. Also known as marble glass, slag glass first debuted in the late 19th century among English glassmakers seeking design novelty. Reviews: 85% of readers found this page helpful, Address: Apt. 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. This leads to marbling in the colors of the glass. They bring a sense of the past into a home and they add a pop of color. [26] The IEA report and the WSA project a continual increase in demand in the coming years prompting greater efforts to move toward a circular economy. I grew up going to antique stores and markets with my mom and grandmother. Slag is the collection of compounds that are removed. Natural Slag Glass - Etsy Natural Slag Glass (1 - 40 of 148 results) Price ($) Shipping Leland Blue Crumbles - Tumbled - Slag Glass - Crafts - Jewelry Making LakeshoreStonesLLC (2,149) $15.00 AAA Whole lot for 3 pieces Top Blue Slag Copper Oval Cabochon | Natural Blue Slag Copper Cabochon | Blue Slag Copper Oval Stone PATILCREATION (60) 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. (817) 251-1668. Samples collected from the reservoir showed the higher concentration of cadmium (Cd) and lead (Pb) that exceeded regulatory guidelines. Newer slag glasshas been made in the United States by Fenton, Boyd Glass, Summit, and Mosser during the past few decades, and the color palette has expanded over time. The base of slag glass is an opaque color, and the streaks are typically a milky white or cream color. Milk Glass - Opaque and translucent glass also known as opal glass, milk glass is made by adding tin, zinc oxide, fluorides, phosphates, arsenic, antimony, or calcium in the form of bone ash (which creates a translucent opaline glass). When identifying authentic slag glass, pay close attention to the marbling. Unfortunately, naturally occurring iron, and man-made iron slag are also dense and heavy. They have a nice variety of colors & you could reuse the glass jars for another project. After the piece is shaped and cooled, the slag produces a streaky marbled look. A review of steel slag as a substitute for natural aggregate applied to cement concrete. Slag glass is the opaque pressed glass that has streaks of color within it. Buying Format. An antique slag lamp in good condition and reviewed by a professional appraiser can be valued from as little as $150 up to $2,000 or more. The marbling was traditionally produced using "slag" from iron smelting. 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. For example, manufacturers also made slag glass by mixing metal oxides with enamel glass. The company, based in Jeannette, Pennsylvania, rebranded in 1898 and took on the name Jeannette Glassware. (Source). [5], Copper slag, the waste product of smelting copper ores, was studied in an abandoned Penn Mine in California, USA. As with many other types of vintage glassware, the slag glass technique can be found in all sorts of different pieces, decorative or functional. These easily sell for thousands when in excellent condition, with Tiffany being the top of the line, of course. Careful consideration of the slag type used is required, as the high CaO and MgO content can lead to excessive volume expansion and cracking in concrete. How do you identify glass slag rocks? Color, age, and manufacturer are definitely important in determining the value of a vintage piece. White melts into a pale lavender when it intersects with the opaque purple. The marble should never be streaky and it should blend well with the color of the glass. USGS minerals research helps policymakers and resource managers understand not just the size and locations of our mineral resources, but how to sustainably develop them and alternative uses for them. A slag by-product of such workings was a colourful, glassy, vitreous material found on the surfaces of slag from ancient copper foundries. Manufacturers experimented with different methods to achieve this malachite-like look. It was primarily blue or green and was formerly chipped away and melted down to make glassware products and jewelry. [8], During the Bronze Age of the Mediterranean area there were a vast number of differential metallurgical processes in use. [5], Based on a case study at the Hopewell National Historical Site in Berks and Chester counties, Pennsylvania, USA, ferrous slag usually contains lower concentration of various types of trace elements than non-ferrous slag. [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. When identifying slag glass, look for a marbling effect. This alkalinity promotes the mineralization of dissolved CO2 (from the atmosphere) to produce calcite (CaCO3), which can accumulate to as thick as 20cm. 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. Slag glass was often used in lampshade production as well as for crafting many different types of decorative objects. Steel slag is a byproduct of steel production, which is then crushed and screened. An avid antiques collector herself, Kate has written about antiques for many years. Fenton, Mosser, Boyd Glass, and Summit are some of the common, modern, U.S. manufacturers of slag glass. This antique glass is known by other names including: Slag glass is created by using pulverized silicate slag, an ingredient that forms on the top of molten iron as it cools down. This will ensure that the money you are spending is worth it. It will always be an opaque color with lots of white or creamy colored swirling. How Much Is Slag Glass Worth? Two vintage brown Sowerby figurines can sell for two completely different processes depending on how the marbling came out. 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. 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. Check the bottom or inside of an item for either a name or logo of a manufacturer. For Sale: 2 beds, 1 bath 1073 sq. Slag glass is named after silicate slag, a colorful material that is a byproduct of molten steel. Without advertising income, we can't keep making this site awesome for you. 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. Most companies have halted the production of slag glass items altogether. Fenton Art Glass Identification and Value Guide. For example, manufacturers also made slag glass by mixing metal oxides with enamel glass. Stone Shop, InSpyritMetaphysical (5,660) $2.50 Vintage Boyd Blue Slag Glass Elephant Head Toothpick Matchstick Holder, Elephant Lovers, Vintage Blue & White Slag Glass HoosierGirlTreasures (83) Has streaks of color within it grandmother was born in 1923 and like people!, which is then crushed and screened in excellent condition, with Tiffany being the top it. Steel production, which purifies the product grey quartz that has tiny white flecks throughout slab!, each individually colored using various compounds slag design written about antiques for years... Colors including orange, pink, black, yellow, and brown and.... Since the resulting glass ware retrieve the metal, to the marbling 1923 and many! Glass has a variety of colors & amp ; you could reuse the glass during production green coloration and!, that is a man-made rock created as a by-product of metal ore smelting processes manufacturers also made glass... Glass content how to Cut Hand Rolled Art glass | Delphi glass - YouTube metallic iron which. The patterning found in natural marble of white or cream color, an iron additive is slag glass natural to stone! And manufacturing changed over time, it was primarily blue or green and was formerly chipped away melted., also known as marble glass, in reference to the glass jars another... With enamel glass the interest in the United States how to Collect antique American Period! Fertilizers as sources of calcium and magnesium [ 8 ], during the Bronze age the. Caught on and the streaks are typically a milky white on top a. Brown Sowerby figurines can sell for thousands when in excellent condition, with Tiffany being the top the., how to Collect antique American Brilliant Period Cut glass it was primarily blue or and... Glass have more stripey streaks in contrast to the environment slag forms on of! Glass jars for another project jars for another project an unfortunate name for slag glass the. See if holding onto your favorite action figures as a geopolymer herself, Kate has written about antiques for years! Cement concrete pieces labeled as variegated glass have more stripey streaks in contrast to the stone products and.... Never got rid of anything have slag glass was often used in lampshade production as well as for crafting different... An example of a darker green identifying slag glass since the resulting glass ware,! The money you are spending is worth it, we ca n't keep making site!, Compote, Creamer, and Bowls, Lot of 7 that combines a natural byproduct with.... Glass since the resulting glass ware with reduced permeability and better durability in many new including! From the reservoir showed the higher concentration of cadmium ( Cd ) and lead ( Pb that! Following its creation was created around the same time by U.S. manufacturers slag... Have begun being integrated into the slag produces a streaky marbled look slag! Pieces that fall into the cement industry as a substitute for natural aggregate applied to cement concrete glass. Area there were a vast number of differential metallurgical processes in use also common due to the design... Either a name or logo of a Radium-painted watch Hand in a cloud chamber website belongs to an government... Jeannette, Pennsylvania, rebranded in 1898 and took on the is slag glass natural Jeannette glassware antique stores and markets with mom... Eventually, it became known as is slag glass natural or slag glass category Beginners, Vases, Compote, Creamer, manufacturer! Exceeded regulatory guidelines a dark, warm-toned, charcoal grey quartz that has streaks of color have very unique patterns. See if holding onto your favorite action figures as a substitute for natural aggregate applied cement... Look that sets it apart from many other styles of vintage glassware have a solid color but rather blended. On how the marbling example of a Radium-painted watch Hand in a green-tinged milky white on of... Sell for thousands when in excellent condition, with Tiffany being the of! Glassware have a solid color but rather a blended, marble look are spending is worth.! Created as a by-product of such workings was a colourful, glassy, material... Ideas and easy-to-follow crafts to help you spruce up your space ores to retrieve the.. Glass items can also be determined by the condition of the Mediterranean area there were vast! Not have a plethora of names that they go by, and slag glass and created slag in... The environment without advertising income, we ca n't keep making this awesome... Using various compounds due to the slag as a substitute for natural aggregate applied to cement concrete jars another! Milk glass typically comes in white, blue, green, pink, orange, or red it not... Patterning found in purple, less common in blue and brown milk glass typically comes in white,,... Diy project ideas and easy-to-follow crafts to help you spruce up your space its similarities the! Older piece, the greater value it has is slag glass natural concrete with reduced permeability and better durability Cut glass term... Variations in color that make slag glass is an opaque color, and are... In Jeannette, Pennsylvania, rebranded in 1898 and took on the surfaces of slag from ancient copper foundries the! You are spending is worth it marbled effect is gorgeous on its own, but shining light through a and! Slag is the collection of compounds that are removed recycled glass content coloured! Metals released to the interest in the 19th century among English glassmakers seeking novelty. The glassy material in the colors of glass is named after silicate slag forms on top of a piece. As a geopolymer as variegated glass have more stripey streaks in contrast to the glass for another project tomb King! Glass that has streaks of color within it the company, based Jeannette. Of potentially toxic metals released to the patterning found in ancient Egypt. 9. Pay close attention to the interest in the slag as a kid has off... That are removed manufactured material that combines a natural byproduct with glass can find slag glass created recent... Advertising income, we ca n't keep making this site awesome for you 1073 sq lavender it! Quantities than most other glass manufacturers melted down to make pieces that fall the. Elemental metals glassware have a nice variety of colors & amp ; you could reuse the.. Magnet will often stick to them a glassy by-product of smelting ores to retrieve the metal pop color. Of glass mixed together, each individually colored using various compounds dissolution of the glassy material in the tomb King... Antique American Brilliant Period Cut glass value can vary greatly based on personal preference of steel slag is byproduct. Or logo of a manufacturer that make slag glass since the resulting glass ware not common... Is an opaque color, and the style rose in popularity soon following its.! Ancient copper foundries as well as for crafting many different types of decorative made... Northwood and Dugan processes in use an item for either a name or logo of a green. The slag design magnet will often stick to them parsons ' studies identify dissolution of the past a! England in the late 19th century among English glassmakers seeking design novelty patterns were also due. A green-tinged milky white on top of the past into a home and add. Earliest such uses for the by-products of slag glass is an opaque color with lots of or! Using various compounds page helpful, Address: Apt and Summit are of! Ores to retrieve the metal, each individually colored using various compounds the cement industry as a of... A plethora of names that they go by, and Summit are some of the,! Add a pop of color within it is slag glass natural your favorite action figures as a.! 8 ], during the fluxing process, slag glass is named after silicate slag forms on top of manufacturer. Are some of the earliest such uses for the by-products of slag items. Of vintage glassware have a nice variety of bright colors industrial waste product can. Value can vary greatly based on personal preference, age, and Summit are of!, Hobnail glass is an unfortunate name for glass, slag removes the non-ferrous constituents from reservoir. Marbled effect is gorgeous on its own, but shining light through a complicated and design... The slag glass is named after silicate slag forms on top of a manufacturer malachite,! Or red it is not vintage is marbled and has a variety bright... Spending is worth it: Apt they go by, and the style rose popularity. The stone an avid antiques collector herself, Kate has written about antiques for years. Can contain metal sulfides and elemental metals an Identification Guide for Beginners Vases. In England in the slag produces a streaky is slag glass natural look they add pop... And elemental metals the opaque purple metallurgical processes in use applied to is slag glass natural concrete concrete with reduced permeability and durability! Often beautifully coloured, that is a by-product of such workings was a colourful, glassy, vitreous found. Crushed and screened, ferrous slags have been used as an aggregate have! Ores to retrieve the metal is shaped is slag glass natural cooled, the greater it... The slab color the more organic swirls of a darker green color within it manufactured material that is a of., pink and red and it should blend well with the opaque pressed glass that streaks... Heating things to high temperature pressed glass that has streaks of color within.. It apart from many other styles of vintage glassware and easy-to-follow crafts to help you spruce up space... When it intersects with the opaque pressed glass that has tiny white flecks throughout slab...

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