Endapan Mineral Bijih

Tipe Endapan

Early Magmatic

Pegmatit

Porfiri

Skarn

Epithermal (HS)

Epithermal (LS)

Pengertian

dihasilkan dari proses magmatik langsung, terbentuk dengan cara diseminasi, segregasi, dan injeksi.

hasil kristalisasi magma granitik yang memiliki ukuran kristal sangat besar, pada kondisi larutan dengan kandungan air yang cukup tinggi

terbentuk karena adanya kontak intrusi plutonik intermediet-asam dengan batuan disampingnya.

terbentuk pada kontak intrusi plutonik dengan batuan induk induk karbonat

Dominasimagmatic

Dominasi air meteorik

VHMS

(quartz-alunite, alunitekaolinite, enargite-Au)

Tipe/model endapan :

SEDEX

Merupakan endapan sulfide logam

Endapan ini memiliki host rocks

dasar yang terdapat di sekuen

batuan sedimen, sedimen, umumnya shales

vulkanik submarine. Endapan biji

dan chert.

memiliki kadar sulfide yang sangat

Lowell Gilbert Model dan Diorite

tinggi.

Model

Tipe bijih : Cu-only, Cu-Au, Cu-Mo, Cu-Mo-Au Tekstur

diseminasi, podiform, stratiform.

Fanerik

vein (A, B, C), stockwork, breccia, fracture, porfiritik

pervasive, pervasive, massif massif stratiform, stratiform, vein related

diseminasi, breccia, veins, vuggy quartz

open space filling, balded, comb, colloform,

crustiform,

akumulasi coloform growth zone, banded/layered banded/layered facies antara sulfide

drustiform, pengendapan pengendapan perlapisan perlapisan

cockade, botryoidal.

(bedding,

banding

sulfide

dan mineral hidrotermal lainnya.

laminasi),

diseminasi, stockwork.

Mineral Bijih

kromit, magnetit, ilmenit, pirit, kalkopirit kalkopirit,, pentlandit, pentlandit, pirhotit. pirhotit.

Arsenopirit,

pyrit,

cassiterit,

pirhotit

kalkopirit, emas, tembaga, molybdenite, bornite, magnetit, enargit

emas, tembaga, besi, pirit, pirhotit, pirhotit, magnetite, magnetite, haematite haematite

pirit, enargit, enargit, kalkopirit, tennanite, tennanite, covellit, emas, tellurides,

Arsenopirit, emas, kalkopirit, galena, sphalerit,, elektrum

sulfide (pirit, pirhotit, markasit, arsenopirit, kalkopirit, sfalerit, galena).

pirit, galena, galena, sphalerite sphalerite,, pirhotit

Gambar

Ilmenit mengandung Haematite

Ilmenite dan haematite in Kimberlite pipe

Wolframite dan cassiterite

Chalcopyrite dan rutile di Porphyry Copper

Molybdenite, Chalcopyrite, Quartz.

Sulphide skarn. Pyrite (yellow-white, bottom right) is intergrown with marcasite (white to light pinkwhite, centre bottom), showing strong reflection pleochroism and bireflectance (centre). A lath-shaped marcasite aggregate (top left) is a pseudomorph after pyrrhotite. Chalcopyrite (yellow, top) is intergrown with inclusion-free sphalerite (light grey, centre) and minor pyrargyrite (blue, centre, top left). Dark grey areas are silicate.

Euhedral pyrite within laths of alunite Pentagonal dodecahedron pyrite in auriferous quartz vein.

Subhedral Enargite in vug of silica alteration

Platy sulfide aggregates.

Galena, chalcopyrite, sphalerite, small pyrite

Kalkopirit, sphalerit (Rammelsberg CUZn-Pb SEDEX deposit)

Pyrit, pyrhotit (Rammelsberg CU-ZnPb SEDEX deposit)

Chalcopyrite, bornite, chalcosite, covelline, molybdenite

Tekstur chromite di bijih stratiform dan podiform. a.Fine-grained b. Coarse-grained

Pyrite-enargite-covellite and late covellite in the vug Euhedral - subhedral magnetite (light brown, centre) has thin rims of haematite (white, higher reflectance, centre top) due to incipient martitization. Coarsegrained garnet (light grey, bottom right) is the main phase and is intergrown with other silicates (dark grey, centre right). Black areas are polishing Enargite replace by covellite in the pits. vug

Euhedral marcasite in quartz vein

Pyrit, pyrhotit, magnetit (Rammelsberg CU-Zn-Pb

Tetrahidrite, sphalerit, galena, pyrhotit.

Chromite dan magnetite Intergrowth of enargite and luzonite

Pyrit, chalcopyrite, pyrhotite (Rammenlsberg Cu-Zn_Pb SEDEX deposit

Haematite,Magnetite, Chalcopyrite Enargite-luzonite-chalcopyrite microveinlet in the silica alteration

Chromite, chalcopyrite, rutile di Bushveld deposit Spec of chalcopyrite in the massive tennantite

Sphalerit, chalcopyrite, pyrite (Rammenlsberg Cu-Zn-Pb

Skeletal Magnetite Tennantite-chalcopyrite-telluride assemblage

Pyrit dengan tekstur rim oleh galena, sphalerit (RammenlsbergCu-Zn-Pb

Referensi

Euhedral magnetite (pinkish grey) replaces hematite (light grey blades),

Intergrowth of tennantite, galena, chalcopyrite cementing the early formed pyrite of advanced argilic.

Exolution of Ilmenite (brownish grey) and hematite (light grey)

Pyrite-Tennantite-Emplectite

http://www.atlas-of-ore-


W.D. Sinclair.2007. Porphyry

minerals.com/ix_t_2.htm#q

minerals.com/ix_t_3.htm#d

Deposits.Canada: Geological Association of Canada

https://journals.lib.unb.ca/inde x.php/GC/article/viewFile/33


26/3843 (J. M. Duke. Ore

minerals.com/ix_t_3.htm#j

Deposit Models 7. Magmatic Segregation Deposits of

http://ore.um.ac.ir/parameters/ore/fil

Chromite . Geoscience

emanager/Porphyry%20copper.pdf

Canada. Volume 10. Number 1)

http://www.mdpi.com/2075163X/6/2/46/htm

http://eprints.utas.edu.au/10703/4/ch .5 _PhD_thesis_(full_version)_June_2 010.pdf

http://www.science.smith.edu/ge Myo Min Tun, I Wayan Warmada,

Noel C. White and Jeffrey W.

osciences/skarn/aboutskarn.html

dkk. 2014. HighSulfidation

https://pubs.usgs.gov/of/1995/of

Epithermal Mineralization and Ore

Deposit: Styles, Characteristic, and

r-95-0831/CHAP12.pdf

Mineral Assemblages of Cijulang

Exploration. SEG Newsletter, No. 23,

Prospect, West Jawa, Indonesia. J.SE

pp.1, 9-13.

Asian Appl. Geol, Vol. 6(1), pp 29-38. http://www.minsocam.org/msa/ OpenAccess_publications/Craig _Vaughan/Craig_Vaughan_Chp Noel C. White and Jeffrey W. tr_10.pdf http://www.atlas-of-oreminerals.com/plate64b.htm

Hadenquist. 1995. Epithermal Gold Deposit: Styles,

Hadenquist. 1995. Epithermal Gold

http://www.atlas-of-oreminerals.com/

https://www.esga.org/fileadmin/sga/Mineral_Deposit _Archive/Rammelsberg/Rammelsberg_ Konka, Solomon Gebreselassie. 2015. SGA_MDA.pdf Samuel Abraham, Bheemalingeswara

Geology of Volcanogenic Massive

Wei Zhai, Xiaoming Sun, et al. 2009. Geology, geochemistry, and genesis of Axi: A Paleozoic low-sulfidation type epithermal gold deposit in Xinjiang, China. China: Elsevier.

Sulfide Deposit near Meli, Northwestern Tigray, Northen Ethiopia. Momona Ethiopian Kournal

of Science, V7(1):85-104.

Characteristic, and Exploration. SEG Newsletter, No. 23, pp.1, 9-

http://www.minsocam.org/msa/Op

13.

enAccess_publications/Craig_Vau ghan/Craig_Vaughan_Chptr_10.pd f

ENDAPAN MINERAL DAN MINERAL BIJIH

https://pubs.usgs.gov/of/1995/ofr95-0831/CHAP29.pdf

PERBANDINGAN MINERAL ENDAPAN EARLY MAGMATIC : kromit, magnetit, ilmenit, pirit, kalkopirit,

Mineral Bijih

pentlandit, pirhotit.

NAMA MINERAL KOMPOSISI REFLECTANCE WARNA

Chromite

Magnetit

Ilmenit

Pyrite

FeCr2O4 Low Dark grey-brownish gray

Fe3O4 Medium Gray, commonly with brownish tint

FeS2 Strong Cream to white

HARDNESS

Hard (5.5) >magnetit, ~llmenite

Hard: >pyrrhotite,
FeTiO3 Low Gray-white with brownish, pink, or violet tint Hard: >magnetite,
Hard: >arsenopyrite, >hematite, ~marcasite

PLEOKROIK

Non

Non

Weak

Isotropic

BIREFLECTANCE ANISOTROPISM Isotropic

INTERNAL REFLECTION

Geological Environment Associated minerals

brown-red brown (Mg-Al-rich samples) Absent in Fe-rich samples (rare, only in thinnest sections) Cumulate mineral in ultramafics, meteorites Hematite, ilmenite, magnetite, millerite, pentlandite, pyrrhotite, sperrylite, ulvospinel, velleriite

Not present except when Mn rich

Accessory mineral in igneous and metamorphic rocks, biogenic product Bravoite, chalcopyrite, cubanite, galena, hematite, ilmenite, marcasite, pentlandite, pyrite, pyrrhotite, rutile, sphalerite, ulvospinel, valleriite, zincite

Chalcopyrite

Pentlandit

Pyrhotite

Yellow-brassy yellow

(Fe,Ni)9S8 Strong Light creamy or yellowish

Fe1-xS Strong Creamy pinkish brown

Medium: >galena,
Medium: > chalcopyrite,
Non

Weak

Non

Medium; >>ccp,=pentlandite, <
Strong Strong Grey shades, light greenish gray, brownish gray Rare: dark brown

Isotropic, Occasionally slightly anisotropic with tints of violet, brown, turqoise -

Weak Weak-distint, grey-blue to yellow green

Isotropic

Accessory of igneous and metamorphic rocks, placers (black sand deposits)

Sedimentary,magmatic,metamorphic, hdrothermal

Occurs with magnetite, hematite, apatite, rutile, pyrite, pyrrhotite, chromite, tantalite

Triple junctions of Ilmenite (grey with brownish tint, strong bireflectance, fine exsolution lamellae of hematite)

CuFeS2

Strong: yellow-gray, greenish gray, grayish blue

-

-

Hydrothermal slfides, dissemination in igneous rocks

Basic and ultrabasic intrusive igneous rock

Igneous and metamorphic rocks

Practically all minerals but especially arsenopyrite, chalcopyrite, galena, magnetite, marcasite, pyrrhotite, sphalerite

Chalcopyrite occurs with pyrite, molybdenite,pyrrhotite,pentlandite, bornite, digenite, magnetite, and many others minerals. It often alters along cracks and grain boundaries to covellite, chalcosite, and malachite. Intergrowths occur with tetrahedrite, cubanite, galena, sphalerite

Pentlandite is the principal ore of nickel. Pyrrhotite, chalcopyrite, pyrite, violarite, millerite, cubanite, chromite, ilmenite, magnetite, sperrylite

Arsemopyrite, brannerite, carrolite, chalcopyrite, cobaltite, cubanite, galena, ilmenite, magnetite, marcasite, millerite, pentlandite, pyrite, stannite

Cataclastic pyrite (white) partially replaced by chalcopyrite (yellow)

Massive chalcopyrite (yellow), magnetite (medium grey, partially as rim around chalcopyrite), carbonate matrix (dark grey)

Pentlandite “flames” (light cream) in pyrrhotite (brownish tinted grey), pyrite crystal (white), chalcopyrite (yellow), quartz (dark grey);

Anhedral pyrrhotite (brownish tint, bireflectance), small chalcopyrite grains (yellow);

Skeletal intergrowth of chalcopyrite (yellow) with sphalerite (medium grey), anglesite (medium grey but darker than sphalerite)

Massive pentlandite (yellowish cream) with alteration products along cracks, pyrrhotite (slightly darker cream), chalcopyrite(yellow);

Gambar

Slightly rounded euhedral chrimite (Medium grey), silicates (dark grey)

Slice of euhedral chromite (brown internal reflections in thinnest past), partially serpentised olivine as matrix (bright-yellow internal reflections)

Euhedral magnetite (brownish grey) with crystallographically oriented hematite replacement (light grey), Bushveld, South Africa

Rim of ilmenite (brownish grey pleochroism) around rutile (lamellar twins, bluish to brownish grey pleochroism,

Pyrrhotite (brownish grey shades) with corrugation lamellae;

Magnetite is replaced by chalcopyrite with bornite

bireflectance) in galena (light grey), silicates Framboidal pyrite (cream), barite crystals (dark grey (greyish);

Colloform pyrite (cream, desiccation cracks), galena (light grey, cleavage breakouts),ilmenite (brownish grey, bireflectance), silicates (dark grey);

Pentlandite (cream) with oriented chalcopyrite exsolution (yellow); Massive chalcopyrite replaces py and is mutually intergrown with sphalerite.

ENDAPAN PEGMATITE Mineral bijih NAMA MINERAL KOMPOSISI REFLECTANCE WARNA

: Arsenopirit, pyrit, cassiterit, pirhotit Arsenopyrite

Cassiterite

Pyrite

Pyrhotite

FeAsS Strong White with faint creamy, yellowish, pinksh tint Hard: >loellingite, >magnetite,
SnO2 Low Brownish gray

FeS2 Strong Cream to white

Fe1-xS Strong Creamy pinkish brown

Hard: >>bismuth, >>bismuthinite, >>molybdenite, >stannite


Weak, white with bluish tint to faint reddish yellow BIREFLECTANCE ANISOTROPISM Strong, red violet

Weak-non

Non

Medium; >>ccp,=pentlandite, <
Strong-weak Moderate

INTERNAL REFLECTION Geological Environment Associated minerals

Abundant: whitish yellow to yellow-brown


HARDNESS

PLEOKROIK

High temperature veins, pegmatites, contact metamorphicrocks Commonly associated with hydrothermal gold, also with vein ores of Sn and W in higjtemperature hydrothermal deposits. It is also associated with Ag and Cu ores, galena, sphalerite, pyrite, chalcopyrite.

Granites, pergmatites, alluvial process

Euhedral arsenopyrite (rhombohedral to skeletal, white) in myrmekitic intergrowths of falkmanite (greenish) and galena (light grey);

Cassiterite (medium grey) replaced by stannite (greenish grey), small specs of chalcopyrite (yellow), quartz (dark grey);

Associated with pyrite, arsenopyrite, molybdenite, wolframite, sphalerite, galena, rutile, hematite, magnetite, bismuth, and pyrrhotite. In placer deposits, cassiteritse is found with other detrital heavy mineral.

Strong: yellow-gray, greenish gray, grayish blue -

Sedimentary, magmatic, metamorphic, hdrothermal Practically all minerals but especially arsenopyrite, chalcopyrite, galena, magnetite, marcasite, pyrrhotite, sphalerite





Gambar

Framboidal pyrite (cream), barite crystals (greyish);

Arsenopyrite twin (blue and brown anisotropy), pyrrhotite (greenish grey anisotropy),sphalerite (isotropic, brown internal reflections);

Colloform cassiterite (internal reflections with various brown shades, grey anisotropy visible in dark layers);

“Wood tin” (finely laminated, various brown internal reflections, grey anisotropy);

Arsenopyrite with rim of pyrrhotite (yellow) PPL

Arsenopyrite with rim of pyrrhotite (yellow) PPL

Pyrrhotite (brownish grey shades) with corrugation lamellae; Colloform pyrite (cream, desiccation cracks), galena (light grey, cleavage breakouts),ilmenite (brownish grey, bireflectance), silicates (dark grey);

ENDAPAN PORFIRI Mineral bijih NAMA MINERAL KOMPOSISI REFLECTANCE WARNA HARDNESS

: kalkopirit, emas, tembaga, molybdenite, bornite, magnetit, enargit Gold

Copper

Molybdenite

Bornite

Enargit

Au

Cu Strong Deep pink, tarnishes brown Soft: >chalcosite,
MoS2 Medium-stron g White, pinkish tint Soft:
Cu5 FeS4 Medium Pinkish borown=orange, tarnishehes-purple Soft: >covellite, `/
Cu3AsS4 Medium Light pinkish brown or pinkish gray Medium: >bornite, >galena, ~/>luzonite, ~/>tennantite,
Bright golden yellow Soft: >stibnite,
PLEOKROIK BIREFLECTANCE ANISOTROPISM Isotropic Many scratcg=hes suggest otherwise INTERNAL Blue and green (transmitted light), REFLECTION otherwise opaque Geological Environment

Quartz veins, alluvial deposit, mesothermal, epithermal, vein, VMS placer, IOGC, porphyry, intrusion related

Associated minerals

In quartz veins with pyrite, arsenopyrite, galena,sphalerite, stibnite, tellurides, chalcopyrite, pyrrhotite, Ag-bearing minerals, Bi-bearing minerals, scheelite, tourmaline, and carbonates. In massive sulphide deposits with pyrite, chalcopyrite, galena, sphalerite. In placer deposit with detrital heavy minerals.

Weak Isotropic

Weak, not always noticeable Weak to absent

Rare, deep red basic Precambrian magmatites, at border between oxidation and cementation zone, cap rocks of Cu sulfide veins, volcanic and sedimentary rocks Porphyry, secondary, supergene, magmatic Small amounts of native copper occur associated with cuprite, malachite, azurite in the oxidized supergene zones of primary copper deposit. It also pccurs with chalcocite, enargite, bornite, pyrrhotite, iron, magnetite. In basalt-hosted deposit, with chalcocite, bornite, chalcopyrite, pyrite.

Porphyry, skarn, vein, magmatic, pegmatite

igneous intrusions, hydrothermal Cu ore veins, alteration product of Cu minerals

Occurs in veins and dissemination wiyh purite, Cassiterite, ccp, covellite, digenite, enargite, chalcopyrite, bpornite, cassiterite, wolframite, sphalerite, tetrahedrite-tennantite bismuthinite, others sulphides.

moderate- to low-temperature hydrothermal veins, epithermal, vein, VMS, porphyry

Commonly associated with chalcopyrite, pyrite, bornite,tetrahedrite-tennantite,covellite, digenite, galena, sphalerite

Gambar

Irregular patches of gold (yellow) in pyrite (light cream);

Skeletal copper (light pink) with small specs of cuprite (bluish grey);

Anhedral electrum (yellowish white), pyrite (cream) altered to goethite (bluish grey shades), quartz (dark grey);

Anhedral native copper (pink tint) next to domeykite (grey) in jasper;

Deformed molybdenite platelets (bright to medium grey, strong bireflectance, pressure twinning), pyrrhotite (pinkish grey);

Radial molybdenite (strong grey bireflectance), vaesite (tinted medium grey), silicate (dark grey);

Anhedral bornite (pinkish grey; Ag-rich) replacing pyrite (white), covellite (blue);

Anhedral enargite (pinkish grey; bireflectance) intergrown with tennantite (greenish) and pyrite (light yellow);

Anhedral bornite (pinkish grey; Ag-rich) with relict chalcopyrite lamellae (yellow), covellite (blue); Massive enargite (violet to bluish grey pleochroism), pyrite (cream), quartz (dark grey);

Massive bornite (pinkish grey) replacing individual laminae of colloform chalcopyrite (light yellow);

Enargite (lamellar blue to brown anisotropy), pyrite (isotropic), quartz (milky to multicolour internalreflections);

Au occurs as subhedral crystals within a quartz veinlet that cross-cuts massive arsenopyrite.

Prismatic enargite (ena) with pyrite and chalcopyriteinclusions.

ENDAPAN SKARN Mineral bijih

: emas, tembaga, besi, pirit, pirhotit, magnetite, haematite

NAMA MINERAL KOMPOSISI REFLECTANCE WARNA HARDNESS PLEOKROIK BIREFLECTANCE ANISOTROPISM INTERNAL REFLECTION

Haematite Fe2O3 Medium Gray-white with bluish tint Hard: >goethite, >ilmenite, >magnetite, ~/
Geological Environment Associated minerals

Magmatic,hydrothermal,metamorphic, sedimentary Common as exsolution lense or lamellae in ilmenite or magnetite, or as a host to lamellae pf the same. It is also commonly associated with pyrite, chalcopyrite, bornite, rutile, chromite, cassiterite, goethite, sphalerite, and with siderite, limonite, and quartz.

Gambar

Large clusters of euhedral and twinned hematite (medium grey, bireflectance);

Colloform hematite (bright red internal reflections, brownish grey anisotropy), goethite (bluish grey anisotropy, brown internal reflections);

Euhedral hematite (lamellar light and dark brownish grey anisotropy, red internal reflections in matrix);

Deformed hematite platelets (medium grey) in tiemannite (light grey);

ENDAPAN EPITHERMAL (HS) Mineral bijih

: pirit, enargit, kalkopirit, tennanite, covellit, emas, tellurides,

NAMA MINERAL KOMPOSISI REFLECTANCE WARNA HARDNESS PLEOKROIK BIREFLECTANCE ANISOTROPISM INTERNAL REFLECTION

Tennanite (cu, Fe)12As4S13 Medium Grayish white-greeenish gray-white, greenish shade Medium: ~chalcopyrite, >digenite,
Covellite CuS Medium Indigo-ble with violet tint to bluish white Soft:
Isotropic Brownish res, reddish

Strong: 45 derjat orange-reddish brown

Geological Environment

Hydrothermal veins, contact metamorphic

Oxidation zone of sulfide Cu deposit, high temperature hydrothermal, porphyry, IOCG Commonly seen with copper and iron sulphides (pyrite, ccp, chalcocite, digenite, bornite.) and is derived from them by alteration. Occurs also with enargite, sphalerite, native copper, cuprite, hematite, limonite, gothite, linnaeite, luzonitem tetrahedrite-tennanite.

Associated minerals

Gambar

Anhedral tennantite (greenish grey) between euhedral pyrite crystals (light Covellite (blue, strong bireflectance) replacing bornite (brownish relicts) and chalcopyrite (yellow lamellae); yellow) and intergrown with enargite (pinkish grey);

ENDAPAN EPITHERMAL (LS) Mineral bijih

: Arsenopirit, emas, kalkopirit, galena, sphalerit,, electrum

NAMA MINERAL KOMPOSISI REFLECTANCE WARNA HARDNESS

Arsenopyrite FeAsS Strong White with faint creamy, yellowish, pinkish tint Hard: >loeelingite, >magnetite,
Sphalerite (Zn, Fe)S Low Dark gray spmetimes with brown or blue tint Medium: >chalcopyrite,
Weak

Galena PbS Strong White-light gray Soft: >>acanthite-argentite, >proustite-pyrargyrite,
PLEOKROIK BIREFLECTANCE ANISOTROPISM INTERNAL REFLECTION

Strong, blue, green, reddish brown-yellow -

Isotropic -

Isotropic Common: white, yellow, reddish, reddish brown, color varies with composition and Fe contens


High temperature veins, pegmatites, contact metamorphic rocks Commonly associated with hydrothermal gold, also with vein ores of Sn and W in higj-temperature hydrothermal deposits. It is also associated with Ag and Cu ores, galena, sphalerite, pyrite, chalcopyrite.

Hydrothermal Pb sulfides veins, disseminations in igneous and sedimentary rocks, MVT, VMS, SEDEX Gn is a common mieral, particularly associated with sphalerite, pyrite, ccp, tetrahedrite-tennantite, argentite, lead sulphosalts

Hydrothermal sulfide veins, submarine

Associated minerals

Non

Gn, py, marcasite, ccp, po, arsenopyrite, fluorite, tetrahedrite in all types of sulphides deposits.

Gambar


Massive galena (light grey) with deformation lamellae (“Bleischweif”), chalcopyrite (yellow, at center);

Massive sphalerite (medium grey) with chalcopyrite disease

Skeletal sphalerite (grey) in chalcopyrite (yellow); Arsenopyrite twin (blue and brown anisotropy), pyrrhotite (greenish grey anisotropy), sphalerite (isotropic, brown internal reflections);

Skeletal galena (light grey) in tennantite (greenish grey);

Anhedral Sphalerite (bright green internal reflections); Galena (light grey) replacing anglesite (dark grey);

Alternating zones of iron-rich (dark brown) and iron poor (yellow) sph in vein.

ENDAPAN VHMS Mineral bijih NAMA MINERAL KOMPOSISI REFLECTANCE WARNA HARDNESS

PLEOKROIK BIREFLECTANCE ANISOTROPISM

: sulfide (pirit, pirhotit, markasit, arsenopirit, kalkopirit, sfalerit, galena).

Marcasite FeS2 Strong Yellowish white with greenish or pinkish tint Hard: ~pyrite, >po

Pyrite FeS2 Strong Cream to white

Pyrhotite Fe1-xS Strong Creamy pinkish brown


Medium; >>ccp, =pentlandite, <
Strong: white with brown tint, yellow with green tint

Non

Weak-strong: creamy brown to reddish brown along grain boundaries

Weak

Soft: >>acanthite-argentite, >proustitepyrargyrite,

Strong, blue, green, reddish brown-yellow

-

-

High temperature veins, pegmatites, contact Hydrothermal Pb sulfides veins, metamorphic rocks disseminations in igneous and sedimentary rocks, MVT, VMS, SEDEX Commonly associated with hydrothermal Gn is a common mieral, particularly gold, also with vein ores of Sn a nd W in higj- associated with sphalerite, pyrite, ccp, temperature hydrothermal deposits. It is tetrahedrite-tennantite, argentite, lead also associated with Ag and Cu ores, galena, sulphosalts sphalerite, pyrite, chalcopyrite.

INTERNAL REFLECTION

-



Sedimentary, hydrothermal, secondary , SEDEX, MVT, epithermal, vein

Sedimentary,magmatic, metamorphic, hdrothermal


Practically all minerals but especially arsenopyrite, chalcopyrite, galena, magnetite, marcasite, pyrrhotite, sphalerite




Strong, blue, green-yellow

Associated minerals

Arsenopyrite FeAsS Strong White with faint creamy, yellowish, pinkish tint Hard: >loeelingite, >magnetite,
Galena PbS Strong White-light gray

Sphalerite (Zn, Fe)S Low Dark gray spmetimes with brown or blue tint Medium:>chalcopyrite,
Yellow-brassyyellow

Non

Weak

Isotropic

Isotropic

Weak Weak-distint, grey-blue to yellow green

-

Common: white, yellow, reddish, reddish brown, color varies with composition and Fe contens Hydrothermal sulfide veins, submarine Gn, py, marcasite, ccp, po, arsenopyrite, fluorite, tetrahedrite in all types of sulphides deposits.

Chalcopyrite

CuFeS2

Medium: >galena,
Hydrothermalslfides, dissemination in igneous rocks Chalcopyrite occurs with pyrite, molybdenite,pyrrhotite, pentlandite, bornite, digenite, magnetite, and many others minerals. It often alters along cracks and grain boundaries to covellite, chalcosite, and malachite. Intergrowths occur with tetrahedrite, cubanite, galena, sphalerite

Gambar

Radial marcasite aggregate (white) with thin pyrite coating (cream);

Framboidal pyrite (cream), barite crystals (greyish); Radial marcasite (bluish white and cream pleochroism, bireflectance) partially replaced by pyrite (slightly brighter cream than marcasite);


Pyrrhotite (brownish grey shades) with corrugation lamellae; Arsenopyrite twin (blue and brown anisotropy), pyrrhotite (greenish grey anisotropy),sphalerite (isotropic, brown internal reflections);


Skeletal galena (light grey) in tennantite (greenish grey);


Massive chalcopyrite (yellow), magnetite (medium grey, partially as rim around chalcopyrite), carbonate matrix (dark grey)

Skeletal sphalerite (grey) in chalcopyrite(yellow); Skeletal intergrowth of chalcopyrite (yellow) with sphalerite (medium grey), anglesite (medium grey but darker than sphalerite)

Colloform pyrite (cream, desiccation cracks), galena (light grey, cleavage breakouts),ilmenite (brownish grey, bireflectance), silicates (dark grey);

Marcasite (brown to turquoise), pyrite (isotropic, here dark cream), sphalerite (isotropic), carbonate (bright internal reflections);

Galena (light grey) replacing anglesite (dark grey);

Anhedral Sphalerite (bright green internalreflections); Massive chalcopyrite replaces py and is mutually intergrown with sphalerite.


Mrc, gn, sph, apy

ENDAPAN SEDEX Mineral bijih

:pirit, galena, sphalerite, pirhotit

NAMA MINERAL KOMPOSISI REFLECTANCE

Pyrite FeS2 Strong

Pyrhotite Fe1-xS Strong

Galena PbS Strong

Sphalerite (Zn, Fe)S Low

WARNA HARDNESS

Cream to white Hard: >arsenopyrite, >hematite, ~marcasite Non

Creamy pinkish brown Medium; >>ccp, =pentlandite, <
White-light gray Soft: >>acanthite-argentite, >proustite-pyrargyrite,
Dark gray spmetimes with brown or blue tint Medium: >chalcopyrite,

Isotropic

Isotropic

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-

Common: white, yellow, reddish, reddish brown, color varies with composition and Fe contens

Sedimentary,magmatic, metamorphic,hdrothermal Practically all minerals but especiallyarsenopyrite, chalcopyrite, galena, magnetite, marcasite, pyrrhotite, sphalerite


Hydrothermal Pb sulfides veins, disseminations in igneous and sedimentary rocks, MVT, VMS, SEDEX Gn is a common mieral, particularly associated with sphalerite, pyrite, ccp, tetrahedrite-tennantite, argentite, lead sulphosalts

Hydrothermal sulfide veins, submarine



PLEOKROIK BIREFLECTANCE ANISOTROPISM

INTERNAL REFLECTION Geological Environment Associated minerals



Gn, py, marcasite, ccp, po, arsenopyrite, fluorite, tetrahedrite in all types of sulphides deposits.

Gambar

Framboidal pyrite (cream), barite crystals(greyish);

Pyrrhotite (brownish grey shades) with corrugation lamellae;



Skeletal sphalerite (grey) in chalcopyrite (yellow); Skeletal galena (light grey) in tennantite (greenish grey);

Colloform pyrite (cream, desiccation cracks), galena (light grey, cleavage breakouts), ilmenite

Anhedral Sphalerite (bright green internal reflections); Galena (light grey) replacing anglesite (dark grey);

(brownish grey, bireflectance), silicates (dark grey);


REFERENSI

G. Spry, Paul and Brian L. Gedlinskie. 1987. Tables for Determination of Common Opaque Minerals .Ames, Lowa: The Economic Geology Publishing Company. Marshall, Dan. , C.D. Anglin, and Hamid Mumin.2004. Ore Mineral Atlas. Canada: Brandon University. Pracejus, Bernhard. 2008. The Ore Minerals Under The Microscope: An Optical Guide.Amsterdam:Elsevier

Endapan Mineral Bijih

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