litidionite
A triclinic-pinacoidal mineral containing copper, oxygen, potassium, silicon, and sodium.

litvinskite
A monoclinic-domatic mineral containing hydrogen, manganese, oxygen, silicon, sodium, and zirconium.

liveingite
A monoclinic-sphenoidal lead gray mineral containing arsenic, lead, and sulfur.

livingstoneite
Alternative form of livingstonite (“a mineral”).

livingstonite
A monoclinic-prismatic mineral containing antimony, mercury, and sulfur.

lizardite
Serpentine.

lizardites
plural of lizardite

loadstone
Alternative form of lodestone.

loadstones
plural of loadstone

lodestone
The mineral magnetite.
Any naturally occurring magnet.
The focus of one's attraction or attention

lodestones
plural of lodestone

loellingite
Alternative spelling of löllingite.

loellingites
plural of loellingite

lollingite
Alternative spelling of löllingite.

lollingites
plural of lollingite

lombaardite
Synonym of allanite.

lomonite
laumontite

lomonosovite
A triclinic-pinacoidal mineral containing oxygen, phosphorus, silicon, sodium, and titanium.

londonite
An isometric-hextetrahedral mineral containing aluminum, beryllium, boron, calcium, cesium, iron, lithium, manganese, oxygen, potassium, rubidium, silicon, and sodium.

lonecreekite
An isometric-diploidal colorless mineral containing aluminum, hydrogen, iron, nitrogen, oxygen, and sulfur.

longulite
A kind of crystallite with a slender acicular form.

longulites
plural of longulite

lonsdaleite
A hexagonal-dihexagonal dipyramidal mineral containing carbon. Also called hexagonal diamond.

lonsdaleites
plural of lonsdaleite

lopezite
A rare red triclinic chromate mineral.

lopolith
a mass of volcanic or igneous rock found within strata which has spilled downward into underlaying strata and forms depressed regions.
mass similar to laccolith but concave down

lopoliths
plural of lopolith

lorandite
A monoclinic-prismatic mineral containing arsenic, sulfur, and thallium.

lorenzenite
An orthorhombic-dipyramidal mineral containing oxygen, silicon, sodium, and titanium.

loseyite
A monoclinic-prismatic mineral containing carbon, hydrogen, manganese, oxygen, and zinc.

lotharmeyerite
A monoclinic mineral containing arsenic, calcium, hydrogen, manganese, oxygen, and zinc.

lotrite
Synonym of pumpellyite.

loudounite
A monoclinic mineral containing calcium, hydrogen, oxygen, silicon, sodium, and zirconium.

loughlinite
An orthorhombic pearl white mineral containing hydrogen, magnesium, oxygen, silicon, and sodium.

lourenswalsite
A hexagonal mineral containing aluminum, barium, calcium, hydrogen, iron, magnesium, oxygen, potassium, silicon, and titanium.

lovdarite
An orthorhombic-pyramidal mineral containing aluminum, barium, beryllium, calcium, hydrogen, iron, magnesium, oxygen, phosphorus, potassium, silicon, sodium, and titanium.

loveringite
A trigonal-rhombohedral black mineral containing aluminum, calcium, cerium, chromium, iron, magnesium, oxygen, titanium, vanadium, and zirconium.

lowigite
A particular variety of alunite.

luanheite
A hexagonal-dihexagonal dipyramidal milky white mineral containing mercury and silver.

luberoite
A monoclinic-prismatic bronze brown mineral containing platinum and selenium.

lublinite
Synonym of calcite.

lucullite
A variety of black limestone, often polished for ornamental purposes.

lucullites
plural of lucullite

luddenite
A monoclinic nickel green mineral containing copper, hydrogen, lead, oxygen, and silicon.

ludjibaite
A blue green mineral containing copper, hydrogen, oxygen, and phosphorus.

ludlamite
A monoclinic-prismatic mineral containing hydrogen, iron, magnesium, manganese, oxygen, and phosphorus.

ludlockite
A triclinic-pinacoidal copper red mineral containing arsenic, iron, lead, and oxygen.

ludwigite
An orthorhombic-dipyramidal mineral containing boron, iron, magnesium, and oxygen.

ludwigites
plural of ludwigite

lueshite
An orthorhombic-disphenoidal mineral containing niobium, oxygen, and sodium.

luetheite
A monoclinic-prismatic mineral containing aluminum, arsenic, copper, hydrogen, and oxygen.

luijaurite
Alternative form of lujavrite.

lujaurite
Alternative form of lujavrite.

lujauvrite
Alternative form of lujavrite.

lujavrite
A dark agpaitic nepheline syenite, a peralkaline igneous rock.

lujavrites
plural of lujavrite

lukrahnite
A triclinic-pinacoidal yellow mineral containing arsenic, calcium, copper, hydrogen, iron, oxygen, and zinc.

lulzacite
A triclinic-pinacoidal mineral containing aluminum, hydrogen, iron, magnesium, oxygen, phosphorus, and strontium.

lumacell
Alternative form of lumachel.

lumachel
A grey form of limestone that contains fossil shells, and reflects a fiery play of colours

lumachella
Alternative form of lumachel.

lumachellas
plural of lumachella

lumachels
plural of lumachel

lunijianlaite
A monoclinic mineral containing aluminum, hydrogen, lithium, oxygen, and silicon.

lutecite
Synonym of moganite.

luzonite
A tetragonal-scalenohedral pale brownish pink mineral containing arsenic, copper, and sulfur.

lydite
A variety of black chert.

lydites
plural of lydite

lyngurium
A mythical gemstone supposedly formed from the dried urine of the lynx

lynguriums
plural of lyngurium

lyonsite
An orthorhombic-dipyramidal black mineral containing copper, iron, oxygen, and vanadium.

macaulayite
A monoclinic blood red mineral containing aluminum, hydrogen, iron, oxygen, and silicon.

macedonite
A tetragonal-ditetragonal dipyramidal black mineral containing lead, oxygen, and titanium.

maceral
A component of coal or oil shale.

macerals
plural of maceral

macfallite
A monoclinic-prismatic mineral containing aluminum, calcium, copper, hydrogen, magnesium, manganese, oxygen, silicon, sodium, and vanadium.

machatschkiite
A trigonal-hexagonal scalenohedral colorless mineral containing arsenic, calcium, hydrogen, oxygen, phosphorus, and sulfur.

mackayite
A green or brown transparent mineral, formula Fe³⁺Te²O⁵(OH), found in Esmeralda County, Nevada.

mackayites
plural of mackayite

mackintoshite
Synonym of thorogummite.

mackintoshites
plural of mackintoshite

macle
Chiastolite; so called from the tessellated appearance of a cross-section.
A crystal having a similar tessellated appearance.
A twin crystal.

macles
plural of macle

maclureite
chondrodite

maclureites
plural of maclureite

macphersonite
An orthorhombic-dipyramidal mineral containing carbon, hydrogen, lead, oxygen, and sulfur.

macquartite
A monoclinic-prismatic orange mineral containing chromium, copper, hydrogen, lead, oxygen, and silicon.

macrinite
An amorphous form of maceral

macrinites
plural of macrinite

macrocryst
A relatively large crystal occurring in a mineral deposit, usually defined as one between 0.5 mm and 10 mm in size.

macrocrystal
A relatively large crystal

macrocrystals
plural of macrocrystal

macrocrysts
plural of macrocryst

macrodome
A dome parallel to the longer lateral axis of an orthorhombic crystal

macrodomes
plural of macrodome

macromosaic
A rock composed of a mosaic of relatively large pieces of a mineral, typically quartz

macromosaics
plural of macromosaic

macroprism
A prism of an orthorhombic crystal between the macropinacoid and the unit prism; the corresponding pyramids are called macropyramids.

macroprisms
plural of macroprism

macroseeding
The seeding of crystallization using an intact crystal that has already been grown

macrostep
A relatively large steplike deformation in the structure of a crystal.

macrosteps
plural of macrostep

madocite
An orthorhombic-pyramidal grayish black mineral containing antimony, arsenic, lead, and sulfur.

maenaite
A calcic bostonite mineral.

maenaites
plural of maenaite.

magatama
A curved bead from the Jōmon period in Japan, made from a variety of different gemstones.

magatamas
plural of magatama

magbasite
An orthorhombic mineral containing aluminum, barium, fluorine, iron, magnesium, oxygen, potassium, scandium, and silicon.

maghaemite
Alternative form of maghemite.