1. Mineralogical exhibition of Mátra Museum

2. Minerals of Miocene rhyolites

3. Minerals of Miocene rhyolites

4. 1.
Manganese-oxyde

5. Manganese-oxyde – MnO
Class: Oxides and Hidroxides
Crystal system: cubic
Characteristic crystal form: aggregate of crystals
Hardness: 5,5
Cleavage/Fracture: excellent cleavage/conchooidal fracture
Colour: black
Streak colour: black
Glance: unglazed
Locality: Gyöngyössolymos

6. 2.
Tridymite (SiO2)

7. Tridimite – SiO2
Class: Oxides and Hidroxides
Crystal system: hexagonal
Characteristic crystal form: tabular
Hardness: 7
Cleavage/Fracture: no cleavage/conchooidal fracture
Colour: white
Streak colour:
Glance: glassy lustre
Locality: Gyöngyössolymos

8. Opal (SiO2∙nH2O) and Goethite [a-FeO(OH)]3.
Opal (SiO2∙nH2O) and Goethite [a-FeO(OH)]

9. Opal – SiO2∙nH2O
Class: Oxides and Hidroxides
Crystal system: amorph
Characteristic crystal form: botryoidal, massive, geode
Hardness: 5,5 – 6,5
Cleavage/Fracture: no cleavage/conchoidal fracture
Colour: colourless, white, red, brown
Streak colour: white
Glance: glassy, unglazed, earthy, waxy lustre
Goethite – -FeO(OH)
Crystal system: rhombic
Characteristic crystal form: spiky, fibrous
Hardness: 5 – 5,5
Cleavage/Fracture: excellent cleavage/hooked fracture
Colour: yellow, brown
Streak colour: reddish yellow
Glance: diamond lustre, semi-metallic lustre
Locality: Gyöngyössolymos

10. 4. Opal (SiO2∙nH2O) and Nontronite
[(Na, Ca0,5)0,33(Fe3+,Al)2(Si,Al)4O10(OH)2∙nH2O]

11. Opal – SiO2∙nH2O
Class: Oxides and Hidroxides
Crystal system: amorph
Characteristic crystal form: botryoidal, massive, geode
Hardness: 5,5 – 6,5
Cleavage/Fracture: no cleavage/conchoidal fracture
Colour: colourless, white, red, brown
Streak colour: white
Glance: glassy, unglazed, earthy, waxy lustre
Nontronite – [(Na,Ca0,5)0,33(Fe3+,Al)2(Si,Al)4O10(OH)2]∙nH2O
Class: Silicates
Subclass: Fillosilicates
Crystal system: monoclinic
Characteristic crystal form: earthy, lamellar
Hardness: 5 – 5,5
Cleavage/Fracture: excellent cleavage/hooked fracture
Colour: green, beownish-green
Streak colour: reddish yellow
Glance: unglazed
Locality: Gyöngyössolymos