DR. hill. gendoet hartono

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1 DR. hill. gendoet hartono
Semester 1, Kristal-Mineral GS SKS teori by: DR. hill. gendoet hartono Selasa&Jumat-jam – 09.10 & jam – 10.55 3

2 SILABUS TGS7113 KRISTALOGRAFI - MINERALOGI (2 SKS)
Minggu I PENDAHULUAN Minggu II PENGENALAN KRISTAL Minggu III SISTEM KRISTAL Minggu IV SIFAT/KARAKTERISTIK KRISTAL Minggu V KRISTAL VS MINERAL Minggu VI PEMBENTUKAN & MODIFIKASI MINERAL Aspek Kimia Minggu VII PEMBENTUKAN & MODIFIKASI MINERAL Aspek Fisik Minggu VIII UJIAN TENGAH SEMESTER

3 Pembagian utama dlm klasifikasi kristal-kristal menurut bentuknya :
S I S T E M K R I S T A L 7 Sistem Kristal Pembagian utama dlm klasifikasi kristal-kristal menurut bentuknya : Kubik, Tetragonal, Hexagonal, Trigonal, Ortorombik, Monoklinik & Triklinik

4 Dasar penggolongan sistem kristal :
Jumlah sumbu kristalografi kristal bersumbu tiga dan empat Letak atau posisi sumbu kristalografi semua sumbu saling tegak lurus salah satu sumbu tidak tegak lurus ketiganya saling tegak lurus Perbandingan panjang dari sumbu-sumbu kristalografi tiga sumbu mempunyai parameter yang sama dua sumbu parameternya sama dan satu diantaranya berbeda Nilai sumbu c atau sumbu vertikal Sumbu Kristal : garis bayangan, lurus, yg menembus kristal (bidang-bidang muka kristal) dan melalui pusat kristal

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6 Crystal System (Shape)
Different minerals have different crystal shapes

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10 3 sumbu saling tegak lurus a ┴ b ; b ┴ c ; c ┴ a a = b = c
sumbu a+ dibuat 30o terhadap b- parameter a dibuat 1/3b (b = c = 3a) a+ b+ c+ c- b- a-

11 Mineral Identification Basics
ISOMETRIC CRYSTALS ISOMETRIC Basic Cube a3 a2 a1 ISOMETRIC In this crystal system there are 3 axes. Each has the same length (as indicated by the same letter “a”). They all meet at mutual 90o angles in the center of the crystal. Crystals in this system are typically blocky or ball-like. no notes

12 Cara Menggambar: Рa- / b+ = 300 a : b¯: c = 1 : 3 : 3

13 Mineral Identification Basics
ISOMETRIC CRYSTALS Within this ISOMETRIC crystal model is the OCTAHEDRAL crystal form (yellow) and the TETRAHEDRAL crystal form (shown by the black lines). There are many forms in the ISOMETRIC crystal system. Some examples are the cube, octahedron, tetrahedron, dodecahedron, and the trapezohedron. ISOMETRIC Crystal Model

14 Mineral Identification Basics
ISOMETRIC CRYSTALS ISOMETRIC - Basic Cube a1 a3 a2 a3 a2 a1 Fluorite cube with crystal axes It does not matter which face is selected to represent the a1 face in the isometric crystal system.

15 Mineral Identification Basics
ISOMETRIC BASIC CRYSTAL SHAPES Cube Fluorite Pyrite Cube with Pyritohedron Striations Spinel Octahedron Trapezohedron Garnet The Pyrite crystals are basically cubes, but the striations (grooves) are produced by the crystal form called the Pyritohedron. Garnet - Dodecahedron

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17 Sistem Tetragonal Mempunyai 3 sumbu kristal yg tegak lurus a bc
a = b sama  c berlainan kadang ditulis: a1=a2c

18 Cara menggambar: Рa + /  b--   = 30o a : b : c = 1 : 3 : 6

19 Mineral Identification Basics
TETRAGONAL CRYSTALS TETRAGONAL Two equal, horizontal, mutually perpendicular axes (a1, a2) Vertical axis (c) is perpendicular to the horizontal axes and is of a different length. TETRAGONAL Crystal Axes a1 a2 c c a2 a1 This is an Alternative Crystal Axes no notes

20 Mineral Identification Basics
TETRAGONAL CRYSTALS TETRAGONAL This model shows a tetragonal PRISM enclosing a DIPYRAMID. no notes TETRAGONAL Crystal Model

21 Mineral Identification Basics
TETRAGONAL CRYSTALS no notes WULFENITE Same crystal seen edge on.

22 Mineral Identification Basics
TETRAGONAL CRYSTALS APOPHYLLITE on Stilbite This is the same Apophyllite crystal looking down the “c” axis. These minerals are from Poona, India. The red square shows the position of the pinacoid (perpendicular to the “c” axis).

23 terima kasih See u next week…. Belajar & Berfikirlah !