FreeShip- Imsil A-25, Microcrystalline Silica, Median Size ~5 Micron- (Prompt Rebate On Multi-Item FreeShip Orders!)

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--> For other related silica materials: <--
https://www.etsy.com/shop/NorthernWestStuff?ref=hdr_shop_menu&search_query=silica
We also carry a generic silica that is very fine (not quite as fine as this, however). Look for:
"Silica 525 Mesh" in the results from the above link

In ceramic applications Imsil A-25 is a very finely ground pure microcrystalline silica (median particle size is 5 microns) which is used as an ingredient in glazes and clay bodies. The supplier says: This is a
"Fine quartz, silicon dioxide, and microcrystalline. Melts at 2119 degrees Fahrenheit and combines under heat with a variety of fluxes to make lower temperature ceramic glaze or glass. It increases the thermal expansion in clays and decreases the thermal expansion in ceramic glazes. An increase in the silica content of the glaze will raise the maturing temperature, and increase hardness and resistance to abrasion."

Microcrystalline silica is a very finely divided or “micro” form of quartz physically bound together as loose agglomerates. Although considerably more expensive than silica typically used in ceramic glazes, microcrystalline is considered by some to be the “ultimate” silicate for use in glazes. Microcrystalline silica is a polymorph of silica and originates from silica derived from skeletons of a variety of marine animals. There are three main varieties: flint, chalcedony, jasper. Like quartz, all these varieties undergo inversion to cristobalite with heat.

Sibelco mines and processes this silica. The Cary company markets it mainly as a filler in paints, other coatings, grouts, and sealants. Here is the Technical Data Sheet on it (PDF),
{ https://www.thecarycompany.com/media/pdf/specs/TDS_ImsilFull_Jun2016.pdf } :
"Imsil microcrystalline silica fillers are produced from an inert, naturally occurring alpha quartz with a unique grape-like morphology. Easily wetted and dispersed in either solvent or water-based systems, IMSILs selected for its excellent tint retention, durability over prolonged exposure, and resistance to dirt and weathering.
Interior architectural paints formulated with IMSIL® will exhibit strengthened film integrity, increased stain resistance, more uniform sheen control, and excellent “touch-up” characteristics. Low oil absorption,regardless of particle size, enables formulators to increase loading without adversely affecting critical film properties. Exterior coatings containing IMSIL will better resist weathering, chalking, and under eave frosting. When used in primers, IMSIL also provides the “tooth” necessary for better intercoat adhesion and greater durability in abrasive or corrosive environments. IMSIL has been proven effective in trade salespaints, OEM finishes, marine and industrial coatings, and potting compounds. Finer, micronized grades are useful in formulating higher gloss paints, and systems requiring controlled mineral top size, such as thin coatings and inks. Coarser grades offer texture, traction properties, gloss control, and abrasion resistance in coatings, grouts, sealants, and related building products."
They go on to give sizing specs and chemical analysis in that TDS.

Handle it carefully so dust doesn't become airborne as it can cause silicosis (Wiki says this: "Silica ingested orally is essentially nontoxic...On the other hand, inhaling finely divided crystalline silica dust can lead to silicosis, bronchitis, or cancer, as the dust becomes lodged in the lungs and continuously irritates them, reducing lung capacities").
The Wiki article on it is here:
https://en.wikipedia.org/wiki/Silicon_dioxide
"Silicon dioxide, also known as silica (from the Latin silex), is a chemical compound that is an oxide of silicon with the chemical formula SiO2. It has been known since ancient times. Silica is most commonly found in nature as quartz, as well as in various living organisms. In many parts of the world, silica is the major constituent of sand. Silica is one of the most complex and most abundant families of materials, existing both as several minerals and being produced synthetically. Notable examples include fused quartz, crystal, fumed silica, silica gel, and aerogels. Applications range from structural materials to microelectronics to components used in the food industry."-

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