galena - teaching student specimens of the primary ore of lead with attached matrix - Talsint (?) Morocco - Unit of 5 specimens Brown calcite is an interesting

Brown calcite is an interesting challenge to students who have been introduced to common white or light gray calcite

The Monastery Beach sand came down a creek

it does not expand when it comes in contact with water and is the preferred type of clay for the ceramics industry

The striations may not appear on every face

though they show cubic cleavage

galena - teaching student specimens of the primary ore of lead with attached matrix - Talsint (?) Morocco - Unit of 5 specimens Brown calcite is an interestingGalena PbS Galena is a very common metallic sulfide. It often occurs in cubic crystals and has good cubic cleavage. It is practically the only source of lead, which is used in huge amounts in storage batteries and in shielding from radioactivity. Galena is the Latin name for lead ore. Galena is easily identified by students by its density, metallic luster and its cubic cleavage. Not cleaved into rectangular blocks, though they show cubic cleavage,