tinticite
A triclinic-pinacoidal mineral containing hydrogen, iron, oxygen, phosphorus, and vanadium.

tintinaite
An orthorhombic-dipyramidal lead gray mineral containing antimony, bismuth, copper, lead, silver, and sulfur.

tinzenite
A triclinic-pinacoidal mineral containing aluminum, boron, calcium, hydrogen, iron, manganese, oxygen, and silicon.

tiptopite
A hexagonal-pyramidal colorless mineral containing beryllium, calcium, hydrogen, lithium, oxygen, phosphorus, potassium, and sodium.

tiragalloite
A monoclinic-prismatic orange mineral containing arsenic, hydrogen, manganese, oxygen, and silicon.

tischendorfite
An orthorhombic beige mineral containing lead, mercury, palladium, selenium, and silver.

tisinalite
A trigonal-hexagonal scalenohedral yellow orange mineral containing calcium, hydrogen, iron, manganese, oxygen, silicon, sodium, and titanium.

titanmagnetite
Magnetite containing TiO₂ in solid solution.

titanmagnetites
plural of titanmagnetite

titanowodginite
A titanium-bearing mineral of the wodginite group.

titanowodginites
plural of titanowodginite

titantaramellite
An orthorhombic-dipyramidal mineral containing barium, boron, chlorine, iron, magnesium, oxygen, silicon, and titanium.

tivanite
A monoclinic-prismatic black mineral containing hydrogen, oxygen, titanium, and vanadium.

tlalocite
An orthorhombic mineral containing chlorine, copper, hydrogen, oxygen, tellurium, and zinc.

tlapallite
A monoclinic mineral containing calcium, copper, hydrogen, lead, oxygen, sulfur, and tellurium.

tobelite
A monoclinic-prismatic mineral containing aluminum, hydrogen, nitrogen, oxygen, potassium, and silicon.

tobermorite
An orthorhombic-disphenoidal mineral containing aluminum, calcium, hydrogen, oxygen, and silicon.

tochilinite
A monoclinic bronze black mineral containing hydrogen, iron, magnesium, oxygen, and sulfur.

tokkoite
A triclinic-pinacoidal mineral containing calcium, fluorine, hydrogen, oxygen, potassium, and silicon.

tolbachite
A monoclinic-prismatic mineral containing chlorine and copper.

tolovkite
An isometric-tetartoidal steel gray mineral containing antimony, iridium, and sulfur.

tomichite
A monoclinic-prismatic black mineral containing arsenic, hydrogen, iron, oxygen, titanium, and vanadium.

tomo
A shaft formed in limestone rock dissolved by groundwater.

tomoi
plural of tomos

tomos
An ecclesiastical document, usually promulgated by a synod which communicates or announces important information.

tongbaite
An orthorhombic-dipyramidal light brownish yellow mineral containing carbon and chromium.

tooeleite
A monoclinic-prismatic mineral containing arsenic, hydrogen, iron, oxygen, and sulfur.

topazolite
A yellowish form of andradite

topazolites
plural of topazolite

toph
A kind of sandstone.

tophin
toph

tophs
plural of toph

torreyite
A monoclinic-prismatic bluish white mineral containing hydrogen, magnesium, manganese, oxygen, sulfur, and zinc.

tosudite
An orthorhombic mineral containing aluminum, hydrogen, magnesium, oxygen, silicon, and sodium.

toyohaite
A tetragonal-dipyramidal gray mineral containing iron, silver, sulfur, and tin.

trabzonite
A monoclinic colorless mineral containing calcium, hydrogen, oxygen, and silicon.

trachyandesite
An extrusive igneous rock with a composition between that of trachyte and andesite.

trachyandesites
plural of trachyandesite

trachybasalt
A volcanic rock with a composition between trachyte and basalt.

trachybasalts
plural of trachybasalt

trachyte
A pale igneous rock consisting mostly of potassium feldspar and plagioclase.

tranquillityite
A hexagonal dark red mineral containing iron, oxygen, silicon, titanium, yttrium, and zirconium.

tranquillityites
plural of tranquillityite

trapiche
A mill made of wooden rollers used to extract juice from fruit, originally olives, or from sugar cane.
A star-shaped pattern of inclusions sometimes found in gemstones.

trapiches
plural of trapiche

traskite
A hexagonal-ditrigonal dipyramidal brownish red mineral containing aluminum, barium, calcium, chlorine, fluorine, hydrogen, iron, magnesium, manganese, oxygen, silicon, strontium, and titanium.

trattnerite
A hexagonal-dihexagonal dipyramidal mineral containing aluminum, iron, magnesium, manganese, oxygen, potassium, silicon, sodium, titanium, and zinc.

travertin
Alternative form of travertine.

travertine
A light, porous form of concretionary limestone (or calcite) deposited from solution, and sometimes quarried for building.

travertines
plural of travertine

travertins
plural of travertin

treasurite
A monoclinic-prismatic black mineral containing bismuth, lead, silver, and sulfur.

trechmannite
A trigonal-hexagonal scalenohedral scarlet red mineral containing arsenic, silver, and sulfur.

trembathite
A trigonal-ditrigonal pyramidal mineral containing boron, chlorine, iron, magnesium, and oxygen.

trevorite
A very rare black nickeliferous mineral of the spinel group.

triangulite
A triclinic mineral containing aluminum, hydrogen, oxygen, phosphorus, and uranium.

trichite
A kind of crystallite resembling a bunch of hairs, common in obsidian.
A delicate, hair-like siliceous spicule, found in certain sponges.
A needle-shaped crystal of amylose in starch grains.

trigonite
A monoclinic-domatic mineral containing arsenic, hydrogen, lead, manganese, and oxygen.

trikalsilite
A hexagonal-pyramidal colorless mineral containing aluminum, oxygen, potassium, silicon, and sodium.

trilithionite
A monoclinic-prismatic white mineral containing aluminum, fluorine, lithium, oxygen, potassium, and silicon.

trilliant
A gemstone cut in a triangular shape.

trilliants
plural of trilliant

trimerite
A monoclinic-prismatic mineral containing beryllium, calcium, manganese, oxygen, and silicon.

trimonite
Scheelite.

tripel
A kind of strong pale ale from the Low Countries.
tripoli

tripels
plural of tripel

tripestone
A variety of anhydrite composed of contorted plates, bearing a certain ressemblance to tripe.

triphane
a yellow spodumene

triphanes
plural of triphane

triphylite
An orthorhombic-dipyramidal mineral containing iron, lithium, oxygen, and phosphorus.

trippkeite
A tetragonal-ditetragonal dipyramidal greenish blue mineral containing arsenic, copper, and oxygen.

tripuhyite
A tetragonal-ditetragonal dipyramidal mineral containing antimony, iron, and oxygen.

tristramite
A hexagonal-trapezohedral mineral containing calcium, hydrogen, iron, oxygen, phosphorus, sulfur, and uranium.

trivacancies
plural of trivacancy

trivacancy
A group of three vacancy defects in a crystal.

trogtalite
An isometric-diploidal pink violet mineral containing cobalt and selenium.

trolleite
A monoclinic-prismatic mineral containing aluminum, hydrogen, oxygen, and phosphorus.

trondheimite
Alternative form of trondhjemite.

trondhjemite
A leucocratic intrusive igneous rock, a variety of tonalite in which the plagioclase is mostly in the form of oligoclase.

trondhjemites
plural of trondhjemite

troostite
The mineral willemite with manganese.

troostites
plural of troostite

truscottite
A trigonal white mineral containing calcium, hydrogen, manganese, oxygen, and silicon.

tsaregorodtsevite
An orthorhombic-disphenoidal mineral containing aluminum, carbon, hydrogen, nitrogen, oxygen, and silicon.

tschernichite
A tetragonal-ditetragonal dipyramidal mineral containing aluminum, calcium, hydrogen, oxygen, silicon, and sodium.

tsnigriite
A grey mineral found in gold and silver deposits.

tsugaruite
An orthorhombic silvery lead gray mineral containing arsenic, lead, and sulfur.

tsumcorite
A monoclinic-prismatic mineral containing arsenic, hydrogen, iron, lead, oxygen, and zinc.

tsumgallite
An orthorhombic-dipyramidal mineral containing gallium, germanium, hydrogen, iron, oxygen, silicon, and zinc.

tsumoite
A trigonal-hexagonal scalenohedral silver white mineral containing bismuth and tellurium.

tucekite
A tetragonal-ditetragonal dipyramidal light yellow mineral containing antimony, nickel, and sulfur.