Gregory Rock

Quick answer: Charoite is a purple, swirling silicate mineral found in only one place on Earth: the Murun Massif near

Quick answer: Sodalite and lapis lazuli are both deep blue but are different materials. Lapis lazuli is a rock made

Quick answer: Rhodochrosite is manganese carbonate, colored pink to red by manganese. Banded pink rhodochrosite comes famously from stalactites in

Quick answer: Kyanite is an aluminum silicate whose hardness changes with direction: about 4.5 to 5 along the length of

Quick answer: Diamond and graphite are both pure carbon; the difference is how the atoms are arranged. In diamond, each

Quick answer: Galena is lead sulfide (PbS), the world’s main ore of lead and often an important source of silver.

Quick answer: Sulfur is both a chemical element and a mineral: native sulfur forms bright yellow crystals around volcanic vents

Quick answer: Selenite is the clear, crystalline variety of gypsum (hydrated calcium sulfate). It is so soft (2 on the