Minerals resources including toumaline, sapphire and peridot.
sapphire is a precious gemstone used in jwellery. paridot and tourmaline are semi-precious gemstones. they are less expensive than sapphire.
This PowerPoint helps students to consider the concept of infinity.
Tourmaline, sapphire, peridot
1.
2. The University Of Azad Jammu & Kashmir, Muzaffarabad
Institute Of Geology
Topic: Study of Gemstones: Tourmaline, Sapphire, Peridot
Presented By: Group 03
Roll No: 18-24
Presented To: Sir Shahab Pervez
3. Fig 1. V-shaped Bicolor Tourmaline
Crystals on Smokey Quartz Paprok,
Nuristan, Afghanistan.
I. Tourmaline
4. The Presentation will cover:
Introduction
Locality of Tourmaline in Pakistan & AJK
Physical Properties
Optical Properties
Geological Occurrences of Tourmaline
Uses of Tourmaline
5. Introduction:
The name Tourmaline comes from the Sinhalese term “turmali” meaning “mixed
colored rock.
The stone was first discovered by Dutch trader off the west coast of Italy in the
late 1600’s or early 1700’s. At that time, these green tourmaline were assumed to
be Emerald.
Tourmaline is the birthstone for October, along with Opal. Tourmaline comes in a
staggering variety of colors. This stone has one of the widest color ranges of all
gems.
6. Tourmaline is a crystal boron silicate mineral compounded with elements such as
Aluminum, iron, magnesium, sodium, lithium or potassium.
Tourmaline is classified as a semi-precious stone and the gems comes in a wide
variety of colors.
Tourmaline is not a single mineral, but a group of isomorphous minerals with an
identical crystal lattice.
7. The types of tourmalines include:
1. Rubellite: Tourmaline that is red, purplish red, brownish red, orange-red, or pink.
2. Paraiba: An intense greenish blue, only found in the state of Paraiba, Brazil.
3. Chrome: Intense green.
4. Watermelon: Pink in the center and green around the outside.
8. THE MAP SHOWING THE MAJOR GEMSTONE OCCURRENCES OF PAKISTAN FROM
GEOLOGICAL SURVEY (2002)
9. Locality of Tourmaline in Pakistan &
AJK:
Azad Jammu & Kashmir:
Muzaffarabad District:
Donga Nur
Neelum Valley
Jandaranwala Pegmatite
Nangimali
Palway
Balochistan Region:
Chagai District:
Saindak Cu Deposit
10.
11. Gilgit Baltistan:
Astore District:
Bulochi
Drot Valley
Hunza District:
Upper Hunza Valley
KPK Region:
Chitral District:
Chitral
Mansehra District:
Kaghan Valley
Naran
12. Fig 2. Tourmaline from
Pakistan
Fig 3. Tourmaline from Palway,
Neelum Valley, MZD District,
AJK
13. Physical Properties:
Crystal Structure: Tourmaline is a six member ring or the
cyclosilicates having hexagonal crystal system.
Color: Tourmaline has a variety of colors but pink, red, green, blue
& multicoloured are its most well-known gem colors.
Iron rich tourmaline are black to bluish black to deep brown.
Iithium rich tourmaline are almost any color like blue, green, red,
yellow etc.
Magnesium rich tourmaline varieties are brown to yellow.
14. Hardness: 7-7.5
Specific Gravity: 2.9-3.3
Luster: Vitreous
Streak: White
Fracture: Conchodial to uneven.
Cleavage: Indistinct
Diagnostic Property:
Lack of visible cleavage, prismatic crystal with rounded triangular cross section that
are striated.
15. Optical Properties:
Color & Pleochroism: Essentialy any color is possible, may also be
colorless, strongly pleochroic.
Cleavage: Not visible in thin section, grains are commonly
fractured.
Form: Occur as Euhedral to Subhedral.
Relief: Moderate to high positive relief.
Extinction: Parallel
Optical Character: Uniaxial
16. Geological Occurrences:
Common in many granitic igneous rocks and in some metamorphic
rocks.
Commonly associated with quartz and K-feldspar.
Often associated with Lepidolite, Beryl, Apatite or Flourite.
The variety of tourmaline most often as an accessory minerals in
black Schorl.
17. Uses:
Used as Jewelry gemstones and is cut into all forms and style.
The Piezoelectric nature of tourmaline make it useful as a
component of high pressure gauges.
Black tourmaline used in purification.
18. II. Sapphire
Fig 4. Showing , a selection of both rough
and cut Kashmir sapphires
19. The Presentation will cover:
Introduction
General characteristic
Identification
Optical Properties
Varieties of Sapphire
20. Introduction
Sapphire is a precious gemstone, a variety of minerals
corundum, consisting of Aluminium Oxide, with trace
amount of elements such as iron, titanium chromium,
vanadium or magnesium.
It is typically blue but natural “fancy” sapphire also occur
in yellow, purple, orange & green color.
Commonly natural sapphire are cut and polished into
gemstone and worn in jewelry.
Sapphire is the birthstone for September.
24. Varieties Of Sapphire
Natural Sapphire
Blue Sapphire
Pink Sapphire
Star Sapphire
Padparadscha
25. Natural Sapphire
• Sapphire is one of the two gem-varieties of corundum, the
other being ruby. Although blue is the best-known sapphire
color, they occur in other colors, including gray and black,
and they can be colorless.
• Sapphire and rubies are often found in the same
geographical settings, but they generally have different
geological formations.
• The cost of natural sapphires varies depending on their
color, clarity, size, cut, and overall quality.Sapphires that are
completely untreated are worth far more than those that
have been treated. Geographical origin also has a major
impact on price. For most gems of one carat or more, an
independent report from a respected laboratory.
Fig 5. An uncut, rough yellow
sapphire found at the Spokane
Sapphire Mine near Helena,
Montana.
26. Blue Sapphire
• Blue sapphire exists in various mixtures of its primary
(blue) and secondary hues, various tonal levels (shades)
and at various levels of saturation (vividness).
• Blue sapphires are evaluated based upon the purity of
their blue hue. Violet & green are the most common
secondary hues found in blue sapphires.
• The highest prices are paid for gems that are pure blue
and of vivid saturation. Gems that are of lower
saturation, or are too dark or too light in tone are of less
value. However, color preferences are a personal taste.
Fig 6. Showing the Teardrop-shaped
blue sapphire.
27. Pink Sapphire
• Pink sapphires occur in shades from light to dark pink
and deepen in color as the quantity of chromium
increases.
• The deeper the pink color, the higher their monetary
value. In the United States, a minimum color saturation
must be met to be called a ruby, otherwise the stone is
referred to as a pink sapphire.
Fig 7. Natural Pink Sapphire,
Batakundi-Basil Area (Pakistan)
28. Star Sapphire
• A star sapphire is a type of sapphire that exhibits a star-
like phenomenon known as asterism; red dstones are
known as "star rubies".
• Star sapphires contain intersecting needle-like
inclusions following the underlying crystal structure
that causes the appearance of a six-rayed star shaped
pattern when viewed with a single overhead light
source.
• The value of a star sapphire depends not only on the
weight of the stone, but also the body color, visibility,
and intensity of the asterism. The color of the stone has
more impact on the value than the visibility of the star.
Fig 8. Light color, an oval shaped star sapphire
found in Sri Lanka
29. Padparadscha
• The name is derived from the Sanskrit "padma ranga"
(padma = lotus; ranga = color), a color akin to the lotus
flower.
• Padparadscha is a delicate, light to medium toned, pink-
orange to orange-pink hued corundum, originally found in
Sri Lanka.
• Padparadscha sapphires are rare; the rarest of all is the
totally natural variety, with no sign of artificial treatment.
• Among the fancy (non-blue) sapphires, natural
padparadscha fetch the highest prices.
Fig 9. Faceted padparadscha, found in
Sri Lanka.
30. III. Peridot
Fig 10. Sapat Gali, Naran, Kaghan Valley, Mansehra District, KPK
Province, Pakistan
31. The Presentation will cover:
Introduction
Locality
Identification
Appearance
Geological Occurrence
32. Introduction
It belongs to Olivine family. It is the birthstone for the month
of August & it is said to be put ghosts & demons to flight,
dispel melancholy & foolishness.
Peridot sometimes called chrysolite, is gem-quality olivine and
a silicate mineral with the formula of Mg2SiO4
Peridot is one of only two gems observed to be formed not in
the Earth’s crust, but in molten rock of the upper mantle. Gem-
quality peridot is rare to find on Earth's surface due to its
susceptibility to weathering during transportation from deep
within the mantle to the surface.
33. Locality
It is found near the Kohistan-Kaghan watershed to the NE of
Naran.
It occurs along shear zones and in pockets in dunitic host rocks
and are associated with clinochlore, magnetite and magnesite.
It occurs in the immediate hanging wall of the Indus Suture and
possibly it may be found in the hanging wall of Karakoram
suture.
It represents the basal cumulates of the Sapat Gali (Manshera
District) mafic-ultramafic complex.
34. Identification
Color: Yellow, to yellow-green, olive-green, to brownish, sometimes a
lime-green, to emerald-ish hue.
Fracture: Conchoidal
Mohs Scale Hardness: 6.5-7
Luster: Vitreous
Streak: Colorless
Specific Gravity: 3.2-4.3
Birefringence: +0.036
Melting Point: Very High
Pleochroism: Weak pale yellow-green to yellow, yellow to yellow orange.
35. Appearance
Peridot is one of the few gemstones that occur in only one
color: an olive-green. The intensity and tint of the green,
however, depends on the percentage of iron in the crystal
structure, so the color of individual peridot gems can vary
from yellow, to olive, to brownish-green. In rare cases,
peridot may have a medium-dark toned, pure green with no
secondary yellow hue or brown mask. Lighter colored gems
are due to lower iron concentrations.
36. Geological Occurrence
Olivine, of which peridot is a type, is a common mineral in
mafic and ultramafic rocks, often found in lava and in
peridotite xenoliths of the mantle, which lava carries to the
surface; however, gem-quality peridot occurs in only a
fraction of these settings. Peridots can also be found in
meteorites.
Peridots can be differentiated by size and composition. A
peridot formed as a result of volcanic activity tends to
contain higher concentrations of lithium, nickel and zinc
than those found in meteorites.
37. Olivine is an abundant mineral, but gem-quality peridot is
rather rare due to its chemical instability on Earth's
surface. Olivine is usually found as small grains and tends
to exist in a heavilyweathered state, unsuitable for
decorative use.
Large crystals of forsterite, the variety most often used to
cut peridot gems, are rare; as a result olivine is considered
to be precious.
38. Gallery
Fig 11. Peridot olivine with
minor pyroxene, on vesicular basalt
Fig 12. Olive green peridot. Fig 13. Peridot with milky inclusions