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Do all minerals have crystalline structures?
No, not all minerals have crystalline structures. Some minerals, called amorphous minerals, do not have a regular crystalline structure and instead have a disordered atomic arrangement. Examples of amorphous minerals include opal and glass.
Are there different kinds of opal?
The types of Opal that i am familiar with are White Opal, Fire Opal, Boulder Opal, Black Opal, Crystal Opal, Light Opal, Doublet Opal, Triplet Opal, Common Opal, Synthetic Opal, and Immitation Opal.
What is the opals crystals system?
Opal, being amorphous, is not really a mineral but a mineraloid. One of the scientifically accepted standards defining a mineral is that a mineral must have a crystal structure, which opal lacks. Many scientific groups and references, including the acclaimed Dana's System of Mineralogy, categorize Opal together with the "true" minerals. For this reason, Opal -- as well as other amorphous types that fall under the definition of a mineraloid.
What are some minerals with a greasy luster?
Some minerals that exhibit a greasy luster include turquoise, serpentine, and nepheline. These minerals have a sheen that resembles the appearance of grease or oil on their surfaces.
What class or group does tourmaline opal belongs to?
Tourmaline opal belongs to the silicate class of minerals, specifically in the sub-group known as the cyclosilicates. It is characterized by its unique crystal structure and vibrant play-of-color caused by microscopic silica spheres within the stone.
What gem is not a mineral?
Opal and amber are not minerals.
What is a mineral gem?
Opal and amber are not minerals.
What mineral makes up opal?
Opals are actually not minerals, but are classed as mineraloids. This is because they lack a crystalline structure, yet are mineral in nature.
What are some rare minerals in the US?
There are many minerals which can be found in the US, the rarest ones include Black Opal, Gold, Bauxite, Tin and Aluminium. There are other minerals which are extremely location specific.
How many types of opals are there?
There are 5 basic types of opal. These types are Peruvian Opal, Fire Opal, Girasol Opal, Common opal and Precious Opal.
Why opal water and mercury are not true minerals?
Minerals by definition are solid, naturally occurring inorganic materials with a definite shape and crystalline structure. Opal water and mercury are both liquids lacking a definite shape and crystalline structre.
Is opal a element or a compound?
SiO2 .nH2O
Is a man-made crystal a mineral?
The majority of minerals are crystalline materials.Examples: opal, halite, topaz.
Is opal a cleavage or fracture?
Opal does not have a cleavage or fracture because it lacks a distinct cleavage plane like minerals such as mica or calcite. Instead, opal typically fractures conchoidally, meaning it breaks with smooth, curved surfaces similar to glass.
What is the streak of a opal?
The streak of an opal is typically colorless due to its amorphous structure. It doesn't leave a visible streak on a streak plate like some other minerals do.
Why the mineral opal is often referred to as a mineraloid?
Opal is often referred to as a mineraloid because it lacks a crystal structure, which is a defining characteristic of minerals. Instead, opal is made up of tiny silica spheres arranged in a more random, non-repeating pattern, giving it its unique play-of-color. This amorphous structure sets it apart from traditional minerals.
What is the fracture of opal?
The fracture of an opal can be hard or smooth , An opal can have as many fractures as any other mineral can . Sometimes opal can be smooth , sometimes they can be hard . The fracture of an opal is hard and smooth .
