heulandite
A common mineral of the zeolite group with monoclinic crystals, the most usual form being heulandite-Ca (Ca,Na)₂₋₃Al₃(Al,Si)₂Si₁₃O₃₆·12H₂O.

heulandites
plural of heulandite

hiortdahlite
A rare sorosilicate mineral that contains zirconium, calcium, sodium and fluorine.

hisingerite
An iron silicate with a dark-brown or black color, formula Fe³⁺₂Si₂O₅(OH)₄·2H₂O.

hisingerites
plural of hisingerite

hodgkinsonite
A rare monoclinic zinc manganese silicate mineral with the chemical formula Zn₂MnSiO₄(OH)₂, having a pink, red or yellow-red colour.

hollaite
A form of sovite with high silicate content.

holmquistite
A lithium magnesium aluminium inosilicate mineral, varying in colour from black or violet to sky blue.

holmquistites
plural of holmquistite

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

hornblendes
plural of hornblende

humboldtilite
A variety of melilite with chemical formula (Ca,Na)₂(Si,Mg,Al)₃O₇.

humboltilite
Alternative form of humboldtilite.

hyalophane
A monoclinic crystalline mineral, a barium-rich potassium feldspar.

hyalophanes
plural of hyalophane

hydrogarnet
Any mineral based on a garnet in which one or more silicate anions are replaced by hydroxyls

hydrogarnets
plural of hydrogarnet

hydroxysodalite
A mineral with the chemical formula Al₃HNa₄O₁₃Si₃.

hyperite
Synonym of hypersthenite.

hypersthene
An inosilicate that is an orthorhombic pyroxene.

hypersthenes
plural of hypersthene

hypersthenite
A more or less coarsely crystalline igneous rock, allied to gabbro; an aggregate of labradorite (feldspar) and hypersthene, of plutonic origin.

hypersthenites
plural of hypersthenite

illite
A micaceous phyllosilicate clay mineral with aggregates of grey or white monoclinic crystals.

illites
plural of illite

ilvaite
A black, crystalline sorosilicate of iron and calcium.

ilvaites
plural of ilvaite

imogolite
An aluminium silicate clay mineral found in soils formed from volcanic ash.

imogolites
plural of imogolite

inyoite
A colourless monoclinic mineral with the chemical formula Ca(H₄B₃O₇)(OH)·4H₂O.

jacquesdietrichite
A translucent blue mineral with the chemical formula Cu₂[BO(OH)₂](OH)₃.

jadeite
A pyroxene mineral, a sodium aluminium silicate with the chemical formula Na(Al,Fe³⁺)Si₂O₆, found in metamorphic rocks.

jadeites
plural of jadeite

jadite
Alternative form of jadeite.

jadites
plural of jadite

jaffeite
A hydrated calcium silicate mineral with chemical formula Ca₆Si₂O₇(OH)₆.

jaffeites
plural of jaffeite

jakobssonite
A rare monoclinic white mineral with chemical formula CaAlF₅, found in Iceland.

jamesonite
A dark grey monoclinic sulfosalt mineral with chemical formula Pb₄FeSb₆S₁₄.

jeffersonite
A zinc-containing variety of pyroxene of olive-green color passing into brown.

jimthompsonite
An inosilicate mineral containing iron and magnesium.

joaquinite
A rare silicate mineral.

johnstrupite
A particular titanium silicate mineral.

jordanite
A grey monoclinic sulfosalt mineral with chemical formula Pb₁₄(As,Sb)₆S₂₃.

jordanon
Synonym of microspecies

julienite
A blue monoclinic mineral with chemical name sodium tetrathiocyanatocobaltate(II) octahydrate.

jurbanite
A monoclinic mineral with chemical formula AlSO₄(OH)·₅H₂O.

jurbanites
plural of jurbanite

kaatialaite
A mineral with the chemical formula (Fe(H₂AsO₄)₃·5H₂O).

kadyrelite
A mineral with the chemical formula Hg₄(Br,Cl)₂O.

kadyrelites
plural of kadyrelite

kajanite
A potassic rock consisting of phenocrysts of olivine, phlogopite, and diopside in a groundmass of nepheline, leucite, amphibole, and phlogopite.

kajanites
plural of kajanite.

kamchatkite
An orthorhombic-pyramidal greenish brown mineral with the chemical formula KCu₃(SO₄)₂OCl.

kaolinite
A common hydrous aluminosilicate mineral found in sediments, soils and sedimentary rocks, Al₂Si₂O₅(OH)₄; one of the kaolin group of minerals.

kaolinites
plural of kaolinite

karenwebberite
A mineral with the chemical formula Na(Fe²⁺,Mn²⁺)PO₄.

karpholite
A fibrous mineral occurring in tufts of a straw-yellow colour. It is a hydrous silicate of alumina and manganese.

karpinskyite
A hydrated aluminosilicate of sodium, beryllium, zinc and magnesium

kentallenite
A monzonite containing olivine.

kentallenites
plural of kentallenite

kerolite
A metamorphic nickel-bearing phyllosilicate mineral similar to talc and serpentine.

kerolites
plural of kerolite

kirschsteinite
A grey orthorhombic silicate mineral of the olivine group.

kirschsteinites
plural of kirschsteinite

kleberite
A mineral with the chemical formula FeTi₆O₁₃.

klipsteinite
A hydrated silicate of manganese and iron

klipsteinites
plural of klipsteinite

knebelite
A silicate mineral, a manganese variety of fayalite that forms dark green orthorhombic crystals.

knebelites
plural of knebelite

kochsandorite
A mineral with the chemical formula CaAl₂(CO₃)₂(OH)₄H₂O.

kogarkoite
A pale blue monoclinic mineral with the chemical formula Na₃(SO₄)F.

kornerupine
A rare boro-silicate mineral with the chemical formula (Mg,Fe²⁺)₄(Al,Fe³⁺)₆(SiO₄,BO₄)₅(O,OH)₂, some varieties of which are valued as gemstones.

kornerupines
plural of kornerupine

kupfferite
A deep green variety of amphibole.

kyanite
A blue neosilicate mineral, Al₂SiO₅, found in metamorphic rocks.

kyanites
plural of kyanite

labradorite
A plagioclase feldspar mineral, calcium sodium aluminum silicate, often very coarsely crystalline, used as a decorative stone for carvings and building façades.

labradorites
plural of labradorite

labuntsovite
A monoclinic mineral which is a complex niobate silicate of potassium, barium, sodium and transition metals.

laihunite
An iron neosilicate of the olivine group

laihunites
plural of laihunite

langasite
A mineral form of lanthanum gallium silicate; it may be grown artificially

langasites
plural of langasite

latiumite
A rare phyllosilicate mineral.

laumonite
Alternative spelling of laumontite.

laumontite
A mineral, of a white color and vitreous luster, with the chemical formula CaAl₂Si₄O₁₂·4H₂O. It is a hydrous silicate of alumina and lime. Exposed to the air, it loses water, becomes opaque, and crumbles.

laumontites
plural of laumontite

lavoisierite
A mineral with the chemical formula Mn²⁺₈[Al₁₀(Mn³⁺Mg)][Si₁₁P]O₄₄(OH)₁₂.

lavoisium
(obsolete) A supposed silvery-white, malleable, metallic chemical element, said to have been discovered in pyrites and some other minerals.

lazurite
A mineral of metamorphosed limestones. Lazurite forms the gemstone lapis lazuli, and crushed lazurite provided the ultramarine color in artists' paint of the Old Masters. Sodalite and lazurite form the sodalite group of silicate minerals. Chemical composition: Sodium aluminum silicate with sulphur, Na₄₋₅Al₃Si₃O₁₂S.

lazurites
plural of lazurite

leonhardite
An evaporite, consisting of a calcium aluminosilicate

lepidomelane
A black iron-potash mica, usually found in granitic rocks in small six-sided tables, or as an aggregation of minute opaque scales.

lepidomelanes
plural of lepidomelane

lestiwarite
The aplitic dyke-rock that accompanies nephelite-syenites in Norway and Finland, composed chiefly of alkali feldspar, with very subordinate pyroxene or amphibole.

lestiwarites
plural of lestiwarite

letovicite
A triclinic mineral with chemical formula (NH₃)₃H(SO₄)₂.

leucite
A mineral of silica-poor igneous, plutonic and volcanic rocks. Chemically, leucite is a potassium feldspar with insufficient silica to satisfy the chemical bonds. Because of the unfilled bonds, leucite weathers rapidly and can only be seen as inclusions in freshly broken rock.
A leucoplast.

leucites
plural of leucite

leucophane
Alternative form of leucophanite.

leucophanes
plural of leucophane

leucophanite
A sorosilicate mineral that occurs in pegmatites and alkali igneous complexes as yellow, greenish or white triclinic crystals.

leucophanites
plural of leucophanite