Hornblende vs. Tourmaline — What's the Difference?

Hornblende is a complex inosilicate series of minerals (ferrohornblende – magnesiohornblende). It is not a recognized mineral in its own right, but the name is used as a general or field term, to refer to a dark amphibole.

Tourmaline ( TOOR-mə-lin, -⁠leen) is a crystalline boron silicate mineral compounded with elements such as aluminium, iron, magnesium, sodium, lithium, or potassium. Tourmaline is classified as a semi-precious stone.

The most common mineral in the amphibole group, CaNa(Mg,Fe)4(Al,Fe,Ti)3Si6O22(OH,F)2 commonly green to black, found in igneous and metamorphic rocks.

A complex crystalline silicate containing aluminum, boron, and other elements, used in electronic instrumentation and, especially in its green, clear, and blue varieties, as a gemstone.

(mineral) A green to black amphibole mineral, of complex structure, formed in the late stages of cooling in igneous rock.

(mineral) A complex black or dark-coloured borosilicate mineral, compounded with various chemical elements and considered a semi-precious stone.

The common black, or dark green or brown, variety of amphibole. (See Amphibole.) It belongs to the aluminous division of the species, and is also characterized by its containing considerable iron. Also used as a general term to include the whole species.

A transparent gemstone cut from it.

A green to black mineral of the amphibole group; consists of silicates of calcium and sodium and magnesium and iron

A mineral occurring usually in three-sided or six-sided prisms terminated by rhombohedral or scalenohedral planes. Black tourmaline (schorl) is the most common variety, but there are also other varieties, as the blue (indicolite), red (rubellite), also green, brown, and white. The red and green varieties when transparent are valued as jewels.

A mineral that is a complex borosilicate and hydroxide of aluminum containing iron and magnesium and calcium and lithium and sodium; it is usually black but occurs in transparent colored forms that are used as gemstones