Princeton's WordNet

1. quartz glass, quartz, vitreous silica, lechatelierite, crystal(noun)

   colorless glass made of almost pure silica

2. quartz(noun)

   a hard glossy mineral consisting of silicon dioxide in crystal form; present in most rocks (especially sandstone and granite); yellow sand is quartz with iron oxide impurities

Wiktionary

1. quartz(Noun)

   The most abundant mineral on the earth's surface, of chemical composition silicon dioxide, SiO. It occurs in a variety of forms, both crystalline and amorphous. Found in every environment.

Origin: Quarz, from twarc, probably from a West Slavic language (compare Czech tvrdý, Polish twardy, Russian твёрдый), from тврьдъ, from tvьrdъ.

Webster Dictionary

1. Quartz(noun)

   a form of silica, or silicon dioxide (SiO2), occurring in hexagonal crystals, which are commonly colorless and transparent, but sometimes also yellow, brown, purple, green, and of other colors; also in cryptocrystalline massive forms varying in color and degree of transparency, being sometimes opaque

U.S. National Library of Medicine

1. Quartz

   Quartz (SiO2). A glassy or crystalline form of silicon dioxide. Many colored varieties are semiprecious stones. (From Grant & Hackh's Chemical Dictionary, 5th ed)

The Standard Electrical Dictionary

1. Quartz

   A mineral, silica, SiO2. It has recently been used by C. V. Boys and since by others in the making of filaments for torsion suspensions. The mineral is melted, while attached to an arrow or other projectile. It is touched to another piece of quartz or some substance to which it adheres and the arrow is fired off from the bow. A very fine filament of surpassingly good qualities for galvanometer suspension filaments is produced. As a dielectric it is remarkable in possessing but one-ninth the residual capacity of glass.

• kwartsAfrikaans
• كوارْتز: صُوّان شَفّاف مُتَبَلْوِرArabic
• кварцBulgarian
• quartzoPortuguese (BR)
• křemen(ný)Czech
• Quarz; Quarz-...German
• kvarts; kvarts-Danish
• χαλαζίαςGreek
• cuarzoSpanish
• kvartsEstonian
• کوارتزFarsi
• kvartsiFinnish
• (de, en) quartzFrench
• קְווָארץHebrew
• बिल्लौरHindi
• kvarcCroatian
• kvarcHungarian
• kuarsaIndonesian
• kvarsIcelandic
• quarzo; di quarzoItalian
• 石英(の)Japanese
• 석영Korean
• kvarcasLithuanian
• kvarcsLatvian
• kuarzaMalay
• kwartsDutch
• kvartsNorwegian
• kwarcPolish
• کوارتزPersian
• كوار تس، ځلاندى او پړكيدونكى ډبرې، بلورPashto
• quartzoPortuguese
• (de/din) cuarţRomanian
• кварцRussian
• kremeň; kremeňovýSlovak
• kremenjakSlovenian
• kvarcSerbian
• kvartsSwedish
• แร่ควอทซThai
• kuvarsTurkish
• 石英［的］Chinese (Trad.)
• кварцUkrainian
• سلکا کی ایک معدنی شکل ، صوان سنگ مرمرUrdu
• thạch anhVietnamese
• 石英（的）Chinese (Simp.)