http://www.lavallab.com/laboratory-mill/agate_mortar.htm

Agate Mortar with Pestle

For grinding small sample quantities by hand.

High abrasion resistance, coupled with contamination-free grinding of the sample.

Technical data

Descriptions High purity Brazilian agate (99.91% SiO2)
Resistant to acids (except HF) and solvents
Density 2.6 g/cm3
Mohs' Scratch Hardness 7
Useful volume 9 to 600 ml
Applications Hand mortars are used whenever small sample quantities need to be crushed by hand without contamination.

Agate Mortar and Pestle Sets - SPI Supplies®-
Agate mortar and pestle sets are used when low contaminating grinding is required. ... one is likely to find in a modern scientific laboratory or kitchen. ...
www.2spi.com/catalog/tools/mortar_pestles_agate.shtml



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Note added at 44 mins (2007-09-04 13:10:06 GMT)
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Mortar & Pestle-
Agate mortar and pestles are used for laboratory work where cross contamination must be avoided at all cost, and in fine kitchens grinding herbs and spices ...
www.pelletlab.com/p_g_mortar.shtml