mineral

Green Tourmaline (Verdelite) / Actinolite

Tourmaline group: Na(Mg,Fe,Li,Al,Mn)3Al6(BO3)3Si6O18(OH)4 / Actinolite: Ca2(Mg,Fe)5Si8O22(OH)2

Hardness: 7-7.5 (Tourmaline) or 5.5-6 (Actinolite). Color: Deep olive-green to dark forest green with a metallic to vitreous sheen. Luster: Vitreous to pearly/silky. Crystal structure: Trigonal (Tourmaline) or Monoclinic (Actinolite), displaying prominent parallel striations and prismatic elongate form.

Hardness: 7-7
Luster: Vitreous to pearly/silky

Identified July 24, 2026More mineral →

Explore Green Tourmaline (Verdelite) / Actinolite in the encyclopedia →

Identify your own rocks.

Get a report just like this from any photo, free.

App Store Google Play

Physical properties

Formation & geological history

Formed in igneous pegmatites or metamorphic rocks such as schists and marbles under high pressure and regional/contact thermal conditions.

Uses & applications

Used in lapidary work, gemstone jewelry, crystal healing collections, and as decorative mineral specimens.

Geological facts

Tourmaline exhibits pyroelectric and piezoelectric properties, meaning it can generate an electrical charge when heated or subjected to mechanical pressure.

Field identification & locations

Identified by its prismatic vertical striations, dark green color, distinct pearly-to-vitreous luster, and high hardness. Commonly found in Brazil, Madagascar, Pakistan, and the USA.

Other mineral specimens

See all

Sandstone (with potential mineral staining/concretions)

Arenite (SiO2 based)

sedimentary

Schist

Metamorphic

Sandstone with Mineral Veining or Crust

Sedimentary Sandstone (mostly SiO2 with Fe2O3 tinting)

sedimentary

Potassium Feldspar (Orthoclase)

Orthoclase (KAlSi3O8)

mineral

Gypsum (variety Selenite or Alabaster)

Calcium sulfate dihydrate (CaSO4·2H2O)

Mineral

Nephrite Jade

Nephrite

Mineral/Rock