300px|thumb|kupryt
'''Kupryt''' - tlenków. Należy do grupy minerałów  rzadkich, rozpowszechnionych tylko w niektórych regionach Ziemi.

Nazwa pochodzi od składu chemicznego minerału, którego głównym składnikiem jest miedź (łac. ''cuprum'' = miedź). 

== Właściwości: == 

*Wzór chemiczny:   '''Cu <sub>2</sub> O''' – tlenek miedzi
*Układ krystalograficzny: regularny
*Twardość: 3,5-4
*Gęstość: 6,14
*Rysa: brunatnoczerwona
*Barwa: czerwona w odcieniach do czarnej
*Przełam: półmetaliczny, diamentowy
*Połysk: nierówny, muszlowy
*Łupliwość:  niewyraźna

Tworzy kryształy izometryczne o pokroju igiełkowym, włóknistym (chalkotrychit) o postaci ośmio-, dwunastościanu, rzadziej sześcianu. Występuje w skupieniach zbitych, ziarnistych, ziemistych, pręcikowych. Tworzy też naskorupienia. Jest kruchy, półprzezroczysty (cienkie okruchy przeswiecają), często zawiera domieszki miedzi lub żelaza.  Tworzy paragenezy z miedzią. Reaguje z kwasami i amoniakiem (rozpuszcza się). 

thumb|Cuprite

'''Cuprite''' is a mineral composed of copper(I) oxide Cu<SUB>2</SUB>O, and is a minor ore of copper.

Its dark crystals with red internal reflections are in the isometric system hexoctahedral class, appearing as cubic, octahedral, or dodecahedral forms, or in combinations. Penetration twins frequently occur. In spite of its nice color it is rarely used for jewelry because of its low Mohs hardness of 3.5 to 4. It has a relatively high specific gravity of 6.1, imperfect cleavage and a brittle to conchoidal fracture. The luster is sub-metallic to brilliant adamantine. The "chalcotrichite" variety typically shows greatly elongated (parallel to [001]) capillary or needle like  crystals forms.

It is a secondary mineral which forms in the oxidized zone of copper sulfide deposits. It frequently occurs in association with native copper, azurite, chrysocolla, malachite, tenorite and a variety of iron oxide minerals. It is known as ''ruby copper'' due to its distinctive red color.

Cuprite was first described in 1845 and the name derives from the Latin ''cuprum'' for its copper content.

== Cuprite as a Gemstone ==
thumb|right|Chalcotrichite from Ray, Arizona
Though almost all crystals of cuprite are far too small to yield faceted gemstones, one unique deposit from Onganja, Southwest Africa, which was discovered back in the 1970s, rocked the gemological world by producing some crystals which were both large and gemmy.  Virtually every faceted stone over 1 carat (200 mg) in weight is from this single deposit, which has long been mined out.  Most crystals were immediately snatched up by the major minerological museums of the world, further increasing the rarity of faceted gems.