Turquoise
Physical Properties:
Color: Light blue, sky blue, pale green, blue-green, turquoise-blue, apple green, greenish-gray.
Luster: Sub-vitreous, resinous, waxy, dull, earthy.
Hardness: 5 – 6 (Mohs scale)
Specific Gravity: 2.6 – 2.8
Crystal System: Triclinic
Classification: Turquoise Group
Feldspar
General Formula: XAl(₁₋₂)Si(₃₋₂)O₈
Feldspar is the name for a group of aluminum silicate minerals, collectively representing the most abundant group of minerals found on Earth’s surface. The principal rock-forming minerals within the feldspar group include albite, anorthite, orthoclase, and microcline.
Garnet - Feldspathoid
Formula:
X
3
Z
2
(
SiO
4
)
3
X
3
Z
2
(SiO
4
)
3
Chemical Composition:
X (Divalent site): Mg, Ca,
Fe
2
+
Fe
2+
,
Mn
2
+
Mn
2+
, etc.
Z (Trivalent site): Al,
Fe
3
+
Fe
3+
,
Cr
3
+
Cr
3+
,
V
3
+
V
3+
, etc.
Trace elements: Trace amounts of Sn may substitute for
Fe
3
+
Fe
3+
Taxonomy: Garnet Supergroup
Etymology: The mineral was named Carchedonius Garamanticus (Carthaginian or Garamantic Carbuncle) by Pliny the Elder between 77–79 AD.
Pyroxene
Pyroxene Group
General Formula:
𝐴
𝐷
Si
2
O
6
ADSi
2
O
6
Description:
Pyroxene is a major group of inosilicate (chain silicate) minerals. The group is structurally and chemically classified into two primary subgroups based on crystal system:
Clinopyroxene: Monoclinic system.
Orthopyroxene: Orthorhombic system.
Taxonomy and Nomenclature:
The current standard nomenclature for the pyroxene group was established by Morimoto et al. (1988).
Organic Gemstones
Organic Gemstones: Biological Origins
Overview:
While the majority of gemstones are derived from geological, inorganic processes within the Earth’s crust, a distinct group originates from biological sources. Known as Organic Gemstones, these materials are produced by living organisms or are derived from their fossilized remains.
Key Examples:
Coral: Biogenic structures secreted by marine polyps.
Amber: Fossilized tree resin from ancient forests.
Shell (Mother of Pearl): The nacreous inner lining
Brazilian Amethyst Geode
Due to these beliefs, drinking vessels in the ancient world were frequently carved from amethyst. A popular historical account suggests that these goblets were often used as a clever deception: wine diluted with water would retain a color similar to that of the amethyst vessel, masking the dilution from the drinker. This practice inadvertently reinforced the superstition that the stone itself prevented intoxication, as the consumer was effectively drinking a less potent beverage.Amethyst serves
Quartz group
Color: Colorless, purple, pink, red, black, yellow, brown, green, blue, orange, and various other hues.
Luster: Vitreous.
Hardness:
7
7
(Mohs scale)
Specific Gravity:
2.65
–
2.66
2.65–2.66
Crystal System: Trigonal
Group: Silica Group
Halides including Fluorite Copper Carbonates including Malachite and Azurite
Fluorite | General Description
Fluorite is one of the most beautiful and well-known gemstone minerals. Due to its striking color variety, dazzling transparency, and well-formed crystals, it holds a special place among mineral enthusiasts and gemologists alike.
Composed of calcium fluoride, fluorite typically appears in shades of purple, green, blue, yellow, colorless, and pink. In some remarkable specimens, a single crystal can exhibit multiple colors simultaneously; this enchanting feature make
Other Gemstones (Tiger’s Eye, Obsidian, Sphene)
Sphene (Titanite) | Mineral Profile
Sphene, also known in gemology as Titanite, is a rare and exceptional gemstone mineral, highly regarded for its exceptional luster, diverse color palette, and distinctive crystal habits. A member of the silicate group, Sphene typically manifests in a range of hues, including green, yellow-green, yellowish-brown, orange, and occasionally colorless. When expertly cut and polished, many Sphene specimens exhibit a dazzling brilliance that captures the light in a t
Topaz, Peridot, Zircon, Kyanite
Formula: Al₂(SiO₄)(F,OH)₂
Color: Colorless, white, pale blue, light green, yellow, brownish-yellow, or red
Luster: Vitreous
Hardness: 8
Specific Gravity: 3.4 – 3.6
Crystal System: Orthorhombic
Name: Named after the island of Topazios (now called Zabargad or Saint John’s Island) in the Red Sea. In antiquity, the name was probably used for the gemstone now known as peridot.
Corundum
Gemological Note: Red varieties of corundum are known as Ruby. Varieties of corundum possessing any color other than red are collectively referred to as Sapphire.
Beryl
Gemological Note: Green varieties of beryl are known as Emerald, while the blue variety is known as Aquamarine.
Gemstone Handicrafts -Chalcedony
he Art of Cutting and Crystallization; Gemstone Handicrafts
In this section of the museum, earthly stones are no longer displayed in their raw form; rather, as nature’s canvas in the hands of artists, they have been transformed into novel and captivating forms. In this collection, we have showcased the art of giving life to stone — a place where the fusion of lapidary craftsmanship and the God-given beauty of minerals has produced enduring works of art.
Jasper
Formula: SiO₂
Historically, this name has long been applied to impure, opaque to slightly translucent, microcrystalline chalcedony or chert, typically red to brown or variably colored, usually containing abundant fine inclusions of hematite, iron hydroxides, and other minerals. The name is commonly associated with banded iron formations.
Opal, Carnelian
The origin of this name is uncertain. It may derive from the Sanskrit word “upala”, meaning “stone” or “precious stone,” or from “opalus”, the ancient Latin name for this gem (as noted by Pliny the Elder, 75–79 AD). While Pliny may have referred to this gem as “pedrus”, a modern interpretation by Kostov (2008) questions whether this term was indeed applied to what we recognize as opal in the modern sense.
Silica group
Silica ,composed of silicon and oxygen, is the most abundant compound within the Earth’s crust. Since antiquity, it has served as the fundamental building block for a vast array of stones utilized by humanity. Yet, within this expansive family, certain members have ascended to a distinguished status. Defined by their breathtaking beauty, exceptional hardness, and unique chromatic brilliance, these exceptional specimens have been cherished as precious gemstones throughout history.
Agate
Chemical Formula:
SiO
2
SiO
2
Color: Colorless, gray, red, or white. Due to the presence of various mineral inclusions, multi-colored or variegated specimens are common.
Luster: Waxy to dull.
Hardness:
6.5
–
7
6.5–7
(Mohs scale)
Specific Gravity:
2.6
2.6
Etymology: The name is derived from its historical occurrence in the Achates River in southwestern Sicily.
Earthquakes in Iran
Iran is one of the regions with high seismic potential in the world. However, the distribution of earthquakes across the country is not uniform.
Geological Hazards
Geological hazards are natural events that arise from Earth’s processes (in its crust, interior, and surface) and can pose risks and threats to humans, life, and infrastructure.
Geogenic diseases and their origins
The origin of all elements is the Earth, and both natural and anthropogenic contaminants can transfer from rocks and soil to water, plants, and livestock, and ultimately enter the human body through the food chain.
World Seismotectonic Map
Seismotectonics is a branch of geology that studies the relationship between seismic phenomena and the Earth's tectonic structures and processes.
The Polarizing Light Microscope in Petrography and Paleontology
The polarizing light microscope (PLM) is one of the key instruments used in petrological, mineralogical, and paleontological studies. By utilizing polarized light, it can reveal fine structures and mineral textures that are not visible to the naked eye.
Land Subsidence
Vertical downward movement of the Earth's surface is referred to as land subsidence.
Precious and semi-precious minerals
The precious and semi-precious minerals collection in the geoscience museum of Mashhad is one of the most popular sections, especially for foreign visitors and tourists.
Coin Display Table
The ancient coins displayed in the showcase on the first floor of the museum park are the result of field investigations and sampling conducted by geologists, most of which were discovered at the bottom of mines or during geochemical sampling carried out through panning operations.
