rhodonite
A manganese inosilicate mineral with some substitution by iron and magnesium, of composition (Mn²⁺,Fe,Mg,Ca)SiO₃.

rhodonites
plural of rhodonite

rhyacolite
A glassy feldspar found at Mount Somma in Italy.

richterite
A basic silicate mineral of sodium, potassium, magnesium, manganese, and calcium belonging to the amphibole group

richterites
plural of richterite

riebeckite
A form of amphibole rich in sodium, the fibrous form of which, crocidolite, is a type of asbestos.

riebeckites
plural of riebeckite

ringwoodite
A cubic form of olivine produced under very high pressure, (Mg, Fe²⁺)₂SiO₄.

ringwoodites
plural of ringwoodite

ripidolite
A translucent green chlorite mineral of micaceous structure; a hydrous silicate of alumina, magnesia, and iron.

ripidolites
plural of ripidolite

rivaite
A mineral that is a metadisilicate of calcium and sodium.

rizalite
Synonym of philippinite.

rodingite
A metasomatic rock composed of grossular-andradite garnet, calcic pyroxene, vesuvianite, epidote and scapolite.

rodingites
plural of rodingite

rogermitchellite
A hexagonal mineral that is a complex barium, zirconium, strontium, and sodium basic borosilicate

romeite
A yellow hexoctahedral calcium antimonate mineral with the chemical formula (Ca,Fe,Mn,Na)₂(Sb,Ti)₂O₆(O,OH,F).

romeites
plural of romeite

rosenbergite
A mineral with chemical formula AlF₃·3H₂O.

rowlandite
A rare yttrium silicate mineral.

rruffite
A mineral with the chemical formula Ca₂Cu(AsO₄)₂·2H₂.

rubellite
A red to violet variety of tourmaline used as a gemstone.

rubellites
plural of rubellite

saccharite
A fine granular variety of feldspar.

saleeite
A secondary uranium mineral with the chemical formula Mg(UO₂)₂(PO₄)₂·10(H₂O).

saliotite
A monoclinic phyllosilicate mineral in the smectite group with a pearly lustre.

sanbornite
A rare orthorhombic barium phyllosilicate mineral.

sanidine
A variety of orthoclase feldspar found as tabular crystals embedded in volcanic rocks. Some forms (called moonstone) exhibit adularescence.

sanidines
plural of sanidine

sapphirine
A rare silicate of magnesium and aluminium (with iron as a major impurity), named for its sapphirelike colour.

sapphirines
plural of sapphirine

saussurite
A tough, compact mineral aggregate, of a white, greenish, or greyish colour. It is an aggregate of albite, zoisite, prehnite and other aluminium silicates, and is produced by the alteration of feldspar.

saussurites
plural of saussurite

saxonite
Harzburgite, a peridotite consisting mostly of olivine and low-calcium pyroxene.
Harzburgite, a peridotite consisting mostly of olivine and low-calcium pyroxene.

saxonites
plural of saxonite

scapolite
Any of several mixed sodium and calcium aluminosilicates which also contain chloride, carbonate and sulfate and are found in metamorphic rocks

scapolites
plural of scapolite

schefferite
Synonym of diopside.

schorl
The most common variety of tourmaline.

schorlite
A black variety of tourmaline; Synonym of schorl.

schorlites
plural of schorlite

schorls
plural of schorl

schriesheimite
A variety of pyroxene hornblende peridotite.

scorza
epidote in the form of sand

scottyite
A barium copper silicate mineral.

searlesite
A sodium borosilicate mineral, an important ore of borax.

searlesites
plural of searlesite

sekaninaite
A mineral with the chemical formula ((Fe⁺²,Mg)₂Al₄Si₅O₁₈).

sekaninaites
plural of sekaninaite

selenite
A soft, glassy form of gypsum (chemical formula CaSO₄·2H₂O).
The anion SeO₃²⁻ derived from selenous acid; any salt or ester of selenous acid.

sepiolite
A hydrated magnesium silicate, clay mineral used for carving into decorative articles and smoking pipes.

sepiolites
plural of sepiolite

sericite
A fine-grained mica found in metamorphic rocks

sericites
plural of sericite

shijiangshanite
A light-red to red mineral with the chemical formula Pb3CaAl(Si5O14)(OH)3 · 3H2O.

shorl
Alternative form of schorl.

shorls
plural of shorl

shulamitite
A barium copper silicate mineral with the formula Ca₃TiFe³⁺AlO₈.

siberite
A violet form of tourmaline sometimes used as a gemstone.

siderophyllite
A rare silicate mineral of the mica group.

siderophyllites
plural of siderophyllite

silimanite
Misspelling of sillimanite.

sillenite
A cubic mineral with the chemical formula Bi₁₂SiO₂₀, typically found in association with bismuthite.

sillenites
plural of sillenite

sillimanite
A fibrous neosilicate mineral, polymorphic with andalusite and kyanite, with the chemical formula Al₂SiO₅.

sillimanites
plural of sillimanite

smaltite
A variety of skutterudite with the chemical formula (Co,Fe,Ni)As₂, crystallizing in the cubic system.

smaltites
plural of smaltite

smaragdite
A green foliated kind of amphibole, observed in eclogite and some varieties of gabbro.

smectite
Any of many clay phyllosilicate minerals that have a relatively open structure.

smectites
plural of smectite

sodalite
A mineral of alkaline igneous and plutonic rocks that are low in silica, of the chemical composition of sodium aluminum silicate with chlorine, Na₄Al₃Si₃O₁₂Cl. Pink sodalite is sometimes called hackmanite. Sodalite and lazurite form the sodalite Group of silicate minerals.

sodalites
plural of sodalite

sorosilicate
Any silicate based on the dimeric anion Si₂O₇⁶⁻.

sorosilicates
plural of sorosilicate

spangolite
A dark green, basic aluminosilicate mineral of copper with the chemical formula Cu₆Al(SO₄)(OH)₁₂Cl · 3H₂O.

spangolites
plural of spangolite

specie
Type or kind, in various uses of the phrase in specie.
Money in the form of coins made from precious metal that has an intrinsic value; coinage.

species
A type or kind. (Compare race.)
A type or kind. (Compare race.)
A type or kind. (Compare race.)
A type or kind. (Compare race.)
A type or kind. (Compare race.)
A type or kind. (Compare race.)
An image, an appearance, a spectacle.
An image, an appearance, a spectacle.
Either of the two elements of the Eucharist after they have been consecrated.
Coin, or coined silver, gold, or other metal, used as a circulating medium; specie.
A component part of compound medicine; a simple.

specieses
plural of species

spessartine
A type of garnet, a neosilicate of manganese and aluminium with the chemical formula Mn₃²⁺Al₂(SiO₄)₃.

spessartines
plural of spessartine

spessartite
Alternative form of spessartine.

spodumene
The mineral lithium aluminium inosilicate (LiAl(SiO₃)₂), a pyroxene and ore of lithium, sometimes regarded as a gemstone, which may be greenish, yellowish or pinkish in appearance.

spodumenes
plural of spodumene

staurolite
A dark brown nesosilicate mineral that has crystals that cross and intergrow.

staurolites
plural of staurolite

stetindite
A tetragonal cerium silicate mineral

stibiopalladinite
A palladium-antimony mineral with the chemical formula Pd₅Sb₂.

stibiopalladinites
plural of stibiopalladinite

stilbite
A tectosilicate zeolite mineral consisting of hydrated calcium aluminium silicate, common in volcanic rocks.

stilbites
plural of stilbite

stillwellite
A trigonal-pyramidal rare earth borosilicate mineral.

stilpnomelane
A metamorphic phyllosilicate mineral of the mica group, having the chemical formula K(Fe²⁺,Mg,Fe³⁺)₈(Si,Al)₁₂(O,OH)₂₇.

stilpnomelanes
plural of stilpnomelane

stinkstone
One of the varieties of calcite, barite, and feldspar that emit a foetid odour on being struck.

stinkstones
plural of stinkstone

strass
A rhinestone, brilliant glass used in the manufacture of artificial paste gemstones, consisting essentially of a complex borosilicate of lead and potassium.

strasses
plural of strass

suanite
A monoclinic-prismatic magnesium borate mineral with chemical formula Mg₂B₂O₅.

sunstone
A translucent form of feldspar having flakes of hematite, used as an ornamental stone.
A stone, possibly Icelandic spar, said in late medieval sources to have been used by navigators in the Viking Age and later to find the location of the sun in an overcast sky, possibly via polatization of light.