Basalt fiber

Overview

Production: about 14,200 tons (basalt fiber output in China only (no verified world total), 2019). Main producers: China. [1]

Continuous or discontinuous mineral fiber formed from processed basalt rock.

Feel and behavior

Technical reinforcement.

Where you find it

Composites, industrial fabrics and insulation systems.

Source and geography

Basalt fiber is drawn from melted basalt, a dark volcanic rock rich in silica, alumina, iron, calcium and magnesium oxides, found in many regions including the Ural Mountains, the western United States and numerous Chinese provinces. Unlike glass fiber, it is usually made from crushed rock without added batch chemicals, so its composition varies with the quarry. Industrial production began in the Soviet Union and is now substantial in China, where output in 2019 was reported at about 14,200 tons.

Worth knowing

• Basalt fiber's brown color comes from its iron oxide content, which also makes the melt harder to heat evenly in furnaces.
• A basalt and furan resin prepreg in a 2022 study met the highest fire hazard class for large surfaces inside railway vehicles.

Types, grades and fabrics

Types and grades

Basalt fiber is sold in the same product forms as glass fiber: direct and assembled continuous roving, chopped fiber of set lengths for concrete and plastics, woven fabrics, stitched multiaxial fabrics, mesh and geogrid, pultruded basalt fiber reinforced polymer (BFRP) rebar, and short staple or 'superthin' fibers from flame or centrifugal blowing for insulation. Unlike glass there are no widely standardized composition grades such as E or S, because the melt comes from quarried rock; buyers distinguish products by filament diameter, linear density, sizing chemistry (epoxy-, polyester- or cement-compatible) and the producer's quarry and process. Performance data should therefore be checked batch by batch.

Fabrics and products

Woven basalt fabrics are used for fire blankets, heat shields and welding protection, and as reinforcement in composite panels, pipes and sporting goods. Chopped basalt fiber is mixed into concrete and shotcrete to control cracking, while basalt mesh and BFRP bars replace steel in some slabs and precast elements where corrosion is a concern. Prepregs combine basalt fabric with resins; one study with bio-based furan resin reached the highest fire hazard classification required for large surfaces in railway vehicle interiors. Basalt also appears in cable, pipe and tank reinforcement.

Buying and care

How to judge quality

Ask for a batch-specific test certificate giving tensile strength, modulus, filament diameter and linear density, because properties scatter between producers and batches more than for E-glass. Confirm the sizing matches the resin or cement. For rebar and mesh, look for approvals under the relevant national construction codes and check long-term alkali durability data. The brown color suggests basalt but is not proof; elemental analysis is. Red flags include 'natural' or 'eco' claims without an environmental product declaration, and property figures copied from generic reviews rather than measured on the product.

Care in detail

Handle basalt fabric and roving with gloves, long sleeves and eye protection, since broken filaments irritate skin like glass fiber, and control dust when cutting or grinding composites. Store fabric and roving dry and away from contamination that would weaken resin bonding. Basalt fire blankets should be kept in their container, inspected for holes or brittleness, and replaced after use. Composite parts are cleaned with mild soap and water and protected from ultraviolet light by coatings, as with glass-reinforced parts.

Care at a glance

Use the manufacturer’s application-specific maintenance and handling instructions. Technical performance cannot be inferred from household laundry guidance.

Environmental and social footprint

Basalt fiber avoids the boron-containing batch minerals used in E-glass and melts quarried rock directly, so its production impacts center on quarrying, crushing and furnace energy. Independent life cycle assessments comparing basalt with glass are few, and energy figures in reviews depend on furnace type. Its best-documented environmental benefit is durability: a 2023 review in Materials concluded that adding basalt fiber improved concrete durability measures across many studies, though it flagged research gaps before routine structural use. Non-corroding BFRP rebar may extend service life in marine structures. End-of-life options mirror glass composites and remain limited.

Tradeoffs

Evaluate the specified grade, whole product, useful lifetime and realistic recovery route. A technical property does not establish a lower overall impact.

A useful question to ask: What exact material, product form and documented producer stand behind this name?

Science

Data sheet

Inorganic material

Composition, filament size and product form determine properties and handling.

Structure and chemistry

Basalt fiber is an amorphous silicate glass. Its network is built from SiO4 tetrahedra, with aluminum in the network and iron, calcium, magnesium, sodium, potassium and titanium ions as modifiers. Reported compositions are about 51 to 59 percent SiO2, 14 to 18 percent Al2O3 and 9 to 14 percent iron oxides, which make the fiber brown. Filaments are smooth, round cylinders, because the uniform melt contracts under surface tension as it is drawn and cooled, and diameters range from tens of nanometers to tens of micrometers depending on the process. Surface metal ions hydroxylate, leaving a weakly acidic, negatively charged surface.

From source to yarn

Production has four basic steps: selecting the rock, grinding it, melting it and drawing filaments. The older crucible, or two-step, method first melts raw material into marbles and remelts them for drawing; the tank-kiln, or one-step, method melts and draws continuously, like glass fiber, with lower energy use but more risk of poor homogenization and blocked platinum-rhodium bushings. Iron-rich melts conduct heat poorly and erode electrodes, so furnace design matters. Filaments are sized, commonly with cationic surfactant lubricants that adsorb on the negative surface, and made into rovings, chopped fiber, fabrics and mesh; flame and centrifugal blowing give short-fiber forms.

Performance in use

Basalt fiber has tensile strength and modulus reported above E-glass and close to S-glass, with an elastic modulus about 10 to 25 percent higher than glass fiber. It resists heat well: fabrics kept about 88 to 90 percent residual strength after continuous exposure at 400 C, with lower retention at higher temperatures. Alkaline-earth and alkali oxides give good resistance to alkaline environments, which suits concrete reinforcement, where short basalt fibers improve tensile behavior and crack resistance. Its inert, highly polar surface bonds poorly to resins without surface modification, and property scatter between batches remains a known problem.

How it is identified

Basalt fiber is brown to golden brown, while glass fiber is white or colorless, a quick visual clue that is not conclusive because sizings and coatings can tint glass. It does not burn; sizing chars off. Microscopy shows smooth, round, isotropic glassy filaments much like glass fiber. Scanning electron microscopy with energy-dispersive X-ray spectroscopy distinguishes basalt by its high iron and magnesium content, and elemental analysis is the practical check on 'basalt' claims.

History

Timeline

1. 1922French engineer Paul Dhe proposed manufacturing fiber from basalt, but no production followed. [1]
2. 1954The Soviet Union first extracted basalt fiber. [1]
3. 1985Industrial basalt fiber production began in Ukraine, initially for defense uses and with high energy consumption. [1]
4. Late 1990sA new-generation process cut energy use by about 2.5 times. [1]
5. 2019A continuous tank-kiln basalt fiber line with an annual capacity of 8,000 tons began operating in Deyang, Sichuan, in March. [1]

Basalt fiber is part of the development of mineral-based technical reinforcement. It should be evaluated as a processed material, not simply as untouched rock.

The deeper record

A French engineer, Paul Dhé, proposed basalt fiber manufacture in 1922, but no production followed. The Soviet Union extracted basalt fiber in 1954 and began industrial production in Ukraine in 1985, first for defense uses and with high energy consumption; a new-generation process in the late 1990s cut energy use about 2.5 times. China took up the technology from the 1990s, and in March 2019 a continuous tank-kiln line with an annual capacity of 8,000 tons began operating in Deyang, Sichuan. Uses have since spread into power-grid composites, wind energy and concrete.

Labeling and law

This atlas has not verified a basalt-specific generic fiber name in 16 CFR 303.7 or Annex I of Regulation (EU) No 1007/2011, so for regulated textile products the applicable name should be confirmed against the current texts. Most basalt fiber is sold for construction and composites, where material standards and product data govern. Marketing that calls basalt fiber 'natural' or 'non-toxic' refers to its rock origin; it is still a processed vitreous fiber. For comparison, IARC placed rock (stone) wool in Group 3 in 2001, and dust from cutting should still be controlled.

This describes what rules and standards cover. It is not legal advice; jurisdiction, product form and current rule text control.

Frequently asked

Is basalt fiber better than fiberglass?

It is stiffer and more heat and alkali resistant than E-glass, but it usually costs more per kilogram, has less consistent properties and fewer design standards. For most boats and panels E-glass is still the default; basalt suits heat exposure and some concrete uses.

Is basalt fiber natural?

The raw material is natural rock, but the fiber is a manufactured glass drawn from a melt at high temperature, much like glass fiber. 'Natural' claims describe the feedstock, not the product, and do not imply safety or biodegradability.

Is basalt fiber safe to work with?

Continuous basalt filaments are generally too thick to be respirable, but cutting and grinding can create dust and fragments that irritate skin, eyes and airways. Treat it like glass fiber and follow the safety data sheet.

Sources

• Museum of Fine Arts, Boston: CAMEO materials reference
• Polymers: A review on basalt fiber composites and their applications in clean energy sector and power grids (2022)
• Materials: Research progress on the surface modification of basalt fibers and composites, a review (2025)
• Heliyon: Axial tensile properties of basalt fibre reinforced recycled aggregate concrete (2024)
• Mutation Research: Man-made mineral (vitreous) fibres, evaluations of cancer hazards by the IARC Monographs Programme (2004)
• Materials: Basalt fiber reinforced concrete, a compressive review on durability aspects (2023)
• Polymers: Sustainable prepregs with improved fire behaviour based on furan resin and basalt fibre reinforcement (2022)
• Polymers: Fiber-reinforced composites used in the manufacture of marine decks, a review (2025)

Cite this page

Chaos. (2026). Basalt fiber. In Fibers of Earth: An independent textile atlas. https://www.hendrickresearch.com/fibers/materials/basalt/