Container Glass Application

Anthracite is combined with sulphur and iron salts to produce compounds that colour glass yellow to amber to shades of black. It is also used in the coloration of cement and the production of clear glass to reduce imperfections and improve strength and stability.

  • The addition of carbon increases the reduction potential of molten glass
  • Eliminates gaseous imperfections in glass when used with sodium sulphate
  • Improves glass-melt chemistry during coloration with chrome and manganese dioxide
  • Produces a more consistent, high-quality end product
  • Trims reduction oxidation levels in glass coloration process


  • Natural carbon content range between 79% and 81%
  • 75 to 3 hardness on the Mohs scale (higher than other bituminous coals)
  • 3 to 1.4 relative density (higher than other bituminous coals)

Data Sheets

Glass Reductant Grade

Black Oxide                                                            

Water Filtration grade                     

Solvent Extraction Grade


Due to its unique properties, anthracite glasscarb is sought after for several other applications as well.

Anthracite is an unbeatable reductant for glass, water filtration medium, and colourant, on top of many lesser-known applications. Its versatility comes from possessing the highest carbon content of any other coal or material available, which makes it perfect for colouration, redox, burning, filtration, and much more.

Contact African Pegmatite if you have any questions regarding Anthracite or any other substance mentioned here. Our experts are available and would love to help you find the materials you need to lower your production costs, improve your end product, increase the longevity of your materials, achieve the colours you’re looking for, and make your customers happy.

Anthracite Reductant

Anthracite is combined with sulphur and iron salts to create a glass colourant that strengthens the glass, working as a redox glass carbon. This glass carbon or glasscarb can trim redox and eliminates gaseous imperfections within the glass that can occur upon the addition of sodium sulphate. The colour produced can be any shade from yellow to dark amber, depending on the mixture and the desired colour. Among the options of carbon for glass, anthracite is known to be the coal with the highest carbon content and therefore is thought to be the superior choice of redox glass carbon.

Amber glass colouration achieved with anthracite or carbon is one of the most debated glass colouration techniques in chemical history. The general consensus seems to be that carbon is necessary for achieving an amber colouration in container glass, but that other colourants are necessary as well.

In 1839, K Splitgerber concluded that the reduction of sulphates, which existed purely as soda ash and potash impurities, caused the brown colouration in glass. JT Pelouze confirmed this theory with an experiment that tested the reactions of carbon, boron, silicon, and phosphorus. Glass made with pure raw materials did not turn brown when treated with carbon but turned yellow when sulphides of alkaline earths were introduced. This proved the importance of sulphur when using anthracite reductant to make amber glass.

W Seleznew found in 1882 that basic glasses formed a more stable and deeper amber than acid glasses. He also discovered that the presence of iron sulphides changed the colour to black. Until this study, the black colouration was attributed to a black modification in sulphur. Further studies by A Bork, H Weckerle, and L Springer have shown that carbon alone produced no amber colouration while sulphides alone produced only very weak shades of yellow or amber. It was found necessary to combine both iron and sulphur to produce strong amber colouration. Carbon’s role in creating the rich amber colour is to maintain reducing conditions and stabilize the colour created by the polysulphides.

General Information

Anthracite is the variety of coal with the fewest impurities and the highest carbon content, making it the most efficient and valuable form of coal reductant for glass, as well as invaluable to several other industries. It was created by the fossilization of dense green vegetation in the Carboniferous Age.

As a carbon for glass, anthracite reduces impurities within the glass, strengthening the end product while adding a yellow or amber hue, depending on the needs of the manufacturer. African Pegmatite’s milled anthracite won’t give off a tarry hydrocarbon vapor when heated.

When used as a colourant with chrome and manganese dioxide, the addition of glass reductant will improve the glass-melt chemistry. It helps to trim redox levels during the colouration process. The result is a strong and consistent glass product.

Anthracite has a natural carbon content rage up to 81% and ranks up to a 3 on the Mohs hardness scale. It has a 1.4 relative density. All three of these measurements are higher than what you’ll find in other forms of coal.


Packed in 25/40kg polypropylene bags stretch-wrapped on pallets or 500kg bulk bags. Choose the packaging and shipping arrangement that best suits your needs, from small packaging to bulk bags or custom sizes made just for you. We can accommodate virtually any size, from one metric ton to thousands.


We maintain competitive pricing in an effort to win and retain your business for as long as you need us. Our goal is to meet the needs of every customer, including those with special requests and demanding production schedules.

A 15-day general turnaround for manufacturing allows us to get your compounds to you as quickly as possible, so you can keep up with the demands of your business. Contact us to get in touch with a distributor in your area if you don’t have time to wait for materials.

We currently ship to 44 countries across the world and we’re happy to ship to yours, too. The dependable and professional logistics channels we have in place make it easy to offer great pricing and service regardless of your location.

African Pegmatite

With 48 years as professionals in mining and manufacturing, we have the insight, network, and experience to offer you the very best in quality, service, and efficiency. We’ve been accredited by the ISO 9001 since 2002 and have most recently met the 2015 standard.

We aim to provide the very best materials available to our customers, and become your one-stop shop for colourants, minerals, compounds, and more. Take a look at our general glass page to see all the other glass and supplementary products we have available.

If you’d like to become a distributor of African Pegmatite products, get in touch with us and we’ll customise an arrangement with you.