Wollastonite - Jakobsberg Mine, Varmland, Sweden (Langban area)

From a report compiled by Howie G. - "Wollastonite is a chemically simple mineral composed of calcium and silica, with the chemical formula CaSiO3. It forms when impure limestones react with silica to produce wollastonite and carbon dioxide. Its structure is that of a long chain of silicate tetrahedra sharing common vertices.

Pure wollastonite is bright white. However certain trace metals substituting for calcium can cause other colors; gray, cream, brown, pink, green, or red. It is thought that the most common activator of fluorescence is Mn2+ substituting for calcium. When illuminated by shortwave UV light, the peak emission is at around 555 nm. There are also higher wavelength emissions most likely due to Fe3+ or Cr3+ substitutions.

China is by far the world’s leading source of wollastonite. Other significant producers include India and the United States. Currently the only commercially relevant wollastonite deposits in the US are in upstate New York. (more below)