2. NAMPHIBOLE& PYROXENE
Amphibole is a group of inosilicate minerals that are
typically found in metamorphic and igneous rocks. These
minerals are characterized by their long, thin crystal habit
and a double chain of linked tetrahedra.
The two main types of amphibole are hornblende and actinolite.
Amphibole minerals are often dark-colored
and may exhibit a range of colors, including
green, brown, and black.
3. AMPHIBOLE & PYROXENE
Pyroxene refers to a group of closely related inosilicate minerals commonly
found in igneous and metamorphic rocks. These minerals are characterized by
a single chain of linked silica tetrahedra, forming a crystal structure. Pyroxenes
are typically dark-colored, with colors ranging from green to black, and they
have a prismatic or blocky crystal habit.
The two main types of pyroxene are orthopyroxene (enstatite series) and
clinopyroxene (augite series).
They are essential components in Earth's mantle and are commonly found in
volcanic and plutonic rocks
4. OPTICAL PROPERTY
Birefringence
• Amphibole: Generally exhibits higher birefringence compared to pyroxene.
• Pyroxene: Typically has lower birefringence than amphibole.
Cleavage
• Amphibole: Displays two directions of cleavage at approximately
56 and 124 degrees.
• Pyroxene: Also exhibits two directions of cleavage, but the
angles are different, typically at about 87 and 93 degrees.
5. OPTICAL PROPERTY
Specific Minerals
• Amphibole: Includes minerals like hornblende and actinolite.
• Pyroxene: Includes minerals such as augite and enstatite.
Composition
• Amphibole: Contains double chains of silica tetrahedra in
its crystal structure.
• Pyroxene: Comprises single chains of silica tetrahedra in
its crystal structure.
6. PHYSICAL PROPERTY
Crystal Structure
• Amphibole: Exhibits a double chain structure of linked silica tetrahedra.
• Pyroxene: Features a single chain structure of linked silica tetrahedra.
Cleavage
• Amphibole: Displays two directions of cleavage at
approximately 56 and 124 degrees.
• Pyroxene: Also shows two directions of cleavage,
typically at about 87 and 93 degrees.
7. PHYSICAL PROPERTY
Hardness
• Amphibole: Generally has a hardness ranging from 5 to 6 on the Mohs scale.
• Pyroxene: Tends to be slightly harder, with a hardness ranging from 5 to 7 on the
Mohs scale.
Density
• Amphibole: Typically has a lower density compared to pyroxene.
• Pyroxene: Generally exhibits a higher density.
8. PHYSICAL PROPERTY
Color
• Amphibole: Can range from green to brown to black
• Pyroxene: Commonly appears dark green to black.
Occurrence
• Amphibole: Found in both igneous and metamorphic rocks.
• Pyroxene: Also present in both igneous and metamorphic
rocks.
9. PHYSICAL PROPERTY
Specific Minerals
• Amphibole: Includes minerals like hornblende, actinolite, and anthophyllite.
• Pyroxene: Includes minerals such as augite, diopside, and enstatite.
Chemical Composition
• Amphibole: Generally has more complex chemical
compositions, containing various elements such as iron,
magnesium, calcium, and aluminum.
• Pyroxene: Tends to have a simpler chemical composition
with primarily iron, magnesium, and calcium.
