Bentonite

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General Overview
Bentonite is valuable because of its incredibly small particle size. This, in combination with the active chemistry on the surface of the particles (that makes them hold onto water), makes it the most plastic and impermeable common clay material used in ceramics. Its contribution to working properties in glazes and clay bodies is balanced by the undesirable properties that are also imparted. Thus anyone who uses this material should have their eyes open to its advantages and disadvantages. http://ceramic-materials.com/cermat/material/106.html
Tips, Tricks & How-Tos
Raw bentonite is generally a pale green, buff, cream, or grey material composed of the clay mineral montmorillonite. Its origin can be traced to ancient volcanic eruptions where fine volcanic ash particles were carried by winds and deposited in discrete layers which altered over time from the glassy state to claystone. There is a huge variation in the chemistries of bentonites, it is impossible to specify an average (bentonite is not employed in ceramics for its chemistry). Any generic chemical analysis is thus only an attempt to represent the amounts you might find in a common variety. Because of the high iron content, bentonite is considered a dirty material and thus the tug-of-war between the valuable working properties it imparts and the need for whiteness or pure color that it impedes.
Not Recommended

Safety Information
Note: All safety information contained here within is pure recommendation, and its sole purpose is to help students work safer. This should in no way be considered a professional statement or a replacement for reading product information. Please read all instructions included with products before use.
Availability
Metcalf Store
External Links

NOTE: All information contained within this article is pure opinion. Although this article is intended to help students, it may contain faulty or misleading information. This article is not to be considered professional opinion or advice, and is in no way a replacement for reading all safety/instructional documentation. Always remember to protect yourself when handling/using hazardous materials, as well as test new techniques before using them on projects/work intended to be handed in or used. RISDpedia and its contributers take NO responsibility for the information contained within. RISDpedia is not an official site of the Rhode Island School of Design.