DR. hill. gendoet hartono Semester 1, 2018-2019 Kristal-Mineral GS1126 - 2 SKS teori by: DR. hill. gendoet hartono Selasa&Jumat-jam 07.30 – 09.10 & jam 09.15 – 10.55 3

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

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

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

Crystal System (Shape) Different minerals have different crystal shapes

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-

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

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

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

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.

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

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

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

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

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

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

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).

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