MINERALOGI by: Dr. Maria Ulfa - Spada UNS

(1)

MINERALOGI

by: Dr. Maria Ulfa

(2)

Mineralogi

 Ilmu yang mempelajari mineral- mineral yang berupa unsur-unsur

dan senyawa-senyawa yang terdapat di alam dan merupakan pembentuk bagian-bagian padat dari alam

semesta

 Mineralogi adalah cabang dari geologi.

(3)

(4)

So why mineralogy?

 Minerals are chemical compounds that form from natural earth

processes

 Minerals are basic building blocks of rocks

 Rocks provide record of earth

history and are formed by earth processes

 Geologists

 Study earth history

 Study earth processes

 Mineralogy is the key.

(5)

1. Benda Padat

2. Homogen

3. Terdapat Di Alam

4. Terbentuk Secara Anorganik

5. Mempunyai Komposisi Kimia Pada Batas- batas Tertentu

6. Mempunyai Atom-atom Yang Tersusun Secara Teratur.

MINERAL

(6)

https://pin.it/sy0Oqko

(7)

Kristalograf

 Studi tentang kristal, baik bentuk luar maupun struktur dalam kristal

 Objek studi: unsur-unsur simetri

kristal, simbol bidang kristal, sistem susunan sumbu, bentuk kristal,

perawakan kristal

(8)

Bentuk kristal

 Bentuk dasar : bentuk tunggal, sederhana, semua bidang muka kristalnya sama dan sebangun

 Bentuk kombinasi: beberapa bentuk dasar berlaianan yang membentuk bentuk kombinasi

 Bentuk kembaran

(9)

1. Naturally occurring

 Why not synthetic (man-made)?

 E.g. diamonds

 Corian countertops (quartz)

 Table salt (halite)

 Others?

San Francisco Bay

Salar de Uyuni, Bolivian Altiplano

(10)

2. Homogeneous solid

 Minerals can not be PHYSICALLY broken into new compounds

 How about chemically “broken”?

 What would they break into?

 Why solid?

Chemical reaction: Albite → Na⁺ + Al³⁺ + SiO₄^4- Physical Reaction: Big Feldspar → Little Feldspar

(11)

3. Defned, but not fxed, composition

 The compositions of minerals are

strictly defined (stoichiometry), but can vary between compositions

 For example:

 Calcite is CaCO₃ but will also contain much Mg, Sr, Fe, Mn etc.

 Olivine - (Fe,Mg)₂SiO₄ - is a group of two main minerals:

▪ Fayalite (Fe₂SiO₄)

▪ Forsterite (Mg₂SiO₄)

(12)

4. Ordered atomic arrangement

 Crystallography – how atoms are arranged in space.

 For example:

 Aragonite (CaCO₃) and calcite (CaCO₃) are different minerals but have identical compositions

 This is why minerals are referred to by name rather than formula

 Mineral names include both composition (chemistry) and crystallography