Mariana Soapstone Fire Brick : A fireplace liner of natural stone.

You’ve chosen the perfect mantel & surround – why not design your fireplace using the dove gray beauty of soapstone?

Soapstone’s special mineral properties make it ideal for lining fireplaces. Soapstone is a refractory material: it can withstand high temperatures without cracking.

It is also extremely dense and has a high thermal capacity, so it holds heat and radiates it slowly for hours, improving fireplace efficiency.

But perhaps the best thing is the look: a soft gray fire brick with natural veining & texture. It is a real upgrade to ordinary brick.   And after all, what part of a fireplace to look at most: the firebox! Soapstone fire brick will make a beautiful back drop to your next fire.

Our soapstone fire brick is suitable for use with both gas and wood burning fireplaces, and is often used to line the interiors of Isokern™ or FireRock™ fireplaces.

We stock our Mariana Soapstone Fire brick in four different sizes, and we ship nationwide. Send us an email, or use the inquiry form at the bottom of this page to get prices, installation tips, layout guides, and a calculator that will show you how many soapstone fire bricks you would need for your project.

Mariana Soapstone™ Firebrick FAQ

A metamorphic rock, primarily made of the mineral talc. It is not anything like limestone, marble, granite, slate or sandstone, it’s a totally different animal. It’s also not the rock “Talc” which is translucent and used primarily for carving. Real Soapstone is technically called “Steatite”, and is related to serpentine (green marble). It is reasonably soft and can be scratched with metal. There are so-called “Hard Soapstones” being offered in the market, particularly for the countertop trade, but these are not true soapstone and may not have the same thermal properties as soapstone.

Mariana SoapstoneTM is quarried in Brazil. Stonetrade has been importing Brazilian Soapstone to the US for almost 30 years.

All varieties of true steatite soapstone are gray. The stone varies somewhat in the amount of patterning and white veining, but overall it is a very consistently colored stone. If you want the soapstone to be darker, you could apply a mineral oil/wax formulation, or a color enhancing stone sealer. However, these products are not rated for use in high heat applications, and so should only be considered for decorative fireplaces that will not be actually used.

The mineral talc has a very low thermal coefficient of expansion. So when it is heated and cooled, the stone stays static, and it is therefore much less likely to crack and spall than other natural stones like granite. Plus, soapstone is extremely dense, and its molecular structure permits it to absorb and retain heat for long periods of time. Soapstone is of course non-flammable with a super high melting point, and talc is not chemically reactive to the caustic gasses emitted by burning wood, so it won’t stain or discolor in the same way as marble or limestone. Soapstone is also non-porous so it won’t trap soot.

Yes, we have tested our soapstone and it meets ASTM C-1261 (Standard Specification for Firebox Brick for Residential Fireplaces). If you fire inspector requires it, we can provide a copy of the test results.

Regular (yellow) firebrick is a ceramic product, pressed and fired. It is intended only to insulate and
protect the masonry structure behind it. It has virtually no heat storage capacity and can be crumbly and friable.
It’s very porous and will trap soot and dirt quickly on its exposed surfaces. It is available in a very limited
range of colors and finishes, and can have a raw, unfinished look.

Soapstone firebrick is sawn from large blocks of natural stone, and is much denser. While it too will
protect the masonry behind it from the flames, it also functions as a heat storage system, saving calories that
otherwise would go straight up the chimney, and radiating that heat back into the room.

Honed soapstone bricks show natural veining and texture, and give a much more crisp, finished and
refined look to the lining of a fireplace. If you’ve made the effort to make the surround and mantel look great,
why not make the firebox look great as well? After all, you actually spend the most time looking at the

Experienced masons should have no difficulty in working with soapstone. Soapstone firebricks can be
sawn using an ordinary tile saw with a diamond blade and enough horsepower to cut through 2 ½” of solid
stone. It should always be sawn wet, to reduce the powdery saw dust. Any nicks and scratches on the face of
the stones that occur in sawing or installation can be buffed out with fine grit sandpaper. A random orbital palm
sander works best.

A refractory mortar that is rated for use in fireplaces should always be used, such as Heat-StopTM or
Alsey. Most quality masonry supply centers sell refractory mortar. In general, for consistent results, we
recommend pre-mixed refractory mortar rather than dry mixes.

It is important that the bricks not be very cold when installed, as this will interfere with the mortar
adhesion. Because of their density, the bricks can take hours to warm up – so give them time. Also, be sure to
wipe the bricks clean of any dust before installing, as the dust can interfere with the mortar bond.
Because Soapstone is non-porous, when wet the mortar won’t grab soapstone in the same way as it does
porous yellow firebrick, so usually a mason can lay fewer courses of soapstone firebrick in a day, and some
extra care needs to be taken to avoid the bricks slipping out of position. Once the mortar has set the bond
should be strong. Joints can be 1/8” or even thinner because of the dimensional precision of the bricks.
Soapstone can be cleaned up using muriatic acid or any of the typical chemicals masons use to remove
mortar stains or efflorescence. In fact, Soapstone has historically been used for laboratory work-surfaces
because of its resistance to acids and alkalis. Be careful using abrasive cleaners or tools to clean up soapstone
as they will scratch the surface (although it can be restored with fine grit sandpaper).

The bricks are honed on two faces, one large and one small, which gives the mason the flexibility to lay
them in several different configurations. For example, our Standard bricks (9” x 4 ½” x 2 ½”) can be installed
showing the 9” x 4 ½” face, which results in a soapstone wall thickness of 2 ½”. Or you could lay the same
bricks showing the 9” x 2 ½” face, in which case the wall thickness would be 4 ½”. See our Layout Guide for
more information and images of many different configurations.

Soapstone is better than any other natural stone with heat, but bricks can and do occasionally crack, and
a thicker brick will resist cracking better than a thin one. Plus, a thicker wall gives more soapstone mass to
absorb and radiate heat. So, 2 ½” is the recommended thickness for lining wood-burning fireplaces. However,
many of our customers have successfully lined IsokernTM fireplaces with our 1 ¼” thick bricks. Decorative
fireplaces and gas log fireplaces usually go for 1 ¼” wall thickness.

Soapstone firebricks should only ever be used to line masonry fireplaces that meet code requirements for
minimum clearances to combustibles. Soapstone firebricks should never be used by consumers to line the
inside of “zero clearance” steel fireplace units, because changing the lining material of such units voids the
manufacturer’s warranty and changes the performance characteristics of these UL tested appliances. If you are
considering using soapstone firebrick in an unusual or industrial application, please give us a call to discuss
your idea further.

Melting Point: between 1,000 and 1,500°C
Density: 182 lbs/cubic foot Linear Coefficient of Expansion from 20° to 500° : 0.0000079
Absorption, by weight: 0.2% Compressive strength, (minimum): 4,870 psi

Note: the above data reflect typical values. Soapstone is a product of nature and variations in characteristics may be expected.

  1. Decide what layout of bricks you want – ie: which face size of the bricks do you want to show: Example: I want to show 9″ × 4½” face of standard bricks, with a 2½” thick wall.
  2. Get the square footage of all the walls of your fireplace: Example: back wall 48″ × 30″ = 10 sq ft, plus two side walls 20″ × 30″ = 4.17 sq ft × 2 = 8.33 sq ft, plus floor 48″ × 20″ = 6.67 sq ft. Total square footage to cover: 25 sq ft. Add 10% for waste = 27.5 sq ft.
  3. Divide the square footage of walls by the face square footage of the brick size you want: Example: Standard bricks showing 9 × 4½” face = 0.28 sq ft/brick. Divide 27.5 by 0.28 = 98.21 so you need 99 bricks, 4 cases of 25 standard bricks = 100 bricks.
  4. Or just CONTACT US for a calculator that will work out how many firebrick you need.

We stock four sizes:
Standard: 9″ × 4½” × 2½” (cases of 25)
Split: 9″ × 4½” × 1¼” (cases of 50)
Strip: 9″ × 2½” × 1¼” (cases of 50)
Soap 9” x 2 ½” x 2 ½” (cases of 50)
Each of the sizes (except the soap) has two honed faces: one wide face and one narrow face. So you can lay the bricks up showing either face.
For wood-burning fireplaces, we recommend a minimum wall thickness of 2½”. So you could buy Standards and lay up showing the 9″ × 4½” face,
or Strips and show the 9″ × 1¼” face. Gas fireplaces may be able to use 1¼” thick wall thickness, provided they already meet fire-codes with
the masonry structure behind the bricks.

Our minimum order is 50 standards or 100 splits or 100 strips. We sell full cases only.

We ship nationwide. For a shipping quote to your jobsite, give us the town and zip code, how many bricks you think you’ll need (see How to Calculate), and let us know if we will be shipping to a residential or commercial address. It’s also important for us to know how you plan to unload, as these are heavy pallets. We can offer lift-gate curbside unloading in many locations, but it’s usually less expensive if you can unload with your own forklift or equipment.

For large orders (2000+ bricks) we can supply custom sizes.

We accept checks, money orders or PayPal (some restrictions apply).