This mineral is found in contact metamorphic deposits in limestones. It has the formula (Ca,Na)19(Al,Mg,Fe)13(SiO4)10(Si2O7)4(OH,F,O)10
About 25-30 x 16-25mm x 12-20mm (1.0-1.2" x 0.6-1.0" x 0.5-0.8"). Sizes and shapes vary.
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If your delicate specimen is over 70lbs we will refer you to our local Crating company for safer freight shipping!
*At customer expense.