Diaspore, the new addition in Afghanistan minerals (Raw Diaspore)

During the month of the March 2020 A local Peshawar based small gemological lab CIGTL test a stone with verbal result diaspore 

Here I want to share some observation regarding the new material. 

The main area of the deposit in Goshta, Jalalabad, Afghanistan (near hydro grossular mines in Goshta).

The colour of the stuff is mauve(pale purple) mostly crystals are broken but in good size and clarity (for lapidary) observed. 

I do not observe any colour change material but in incandescent light, the mauve colour slightly changes in lavender (which is the same version of purple with bright colour) 

The material is strongly pleochroic.

No diagnostic absorption spectrum is seen. 

Raman spectra of Diaspore from Afghanistan 

regard 

HUK

 

Diaspore - A Fascinating Mineral

Diaspore is a fascinating mineral with unique properties that make it truly special. Found in various regions around the world, diaspore has gained popularity among mineral enthusiasts due to its distinctive characteristics.

Chemical Composition

Diaspore is an aluminum oxide hydroxide mineral, chemically known as AlO(OH). It was first discovered in the Ural Mountains of Russia in the early 19th century and later named "diaspore" by Frédéric Sarrans, a French mineralogist. This mineral is often found in association with other aluminum-bearing minerals like bauxite, boehmite, and gibbsite.

Pleochroism and Color Change

One of the most intriguing properties of diaspore is its pleochroism. Pleochroism refers to the ability of a mineral to display different colors when viewed from different crystallographic directions. In the case of diaspore, it exhibits a color change phenomenon, appearing greenish-yellow when viewed from one direction and pinkish-brown when viewed from another. This color-changing ability makes diaspore highly sought after by collectors.

Birefringence and Crystal Structure

Another property of diaspore worth mentioning is its strong birefringence. Birefringence is the ability of a mineral to split light into two different rays as it passes through it. When examined under a polarizing microscope, diaspore displays a clear interference color due to its high birefringence. This optical quality adds to its aesthetic appeal.

Diaspore belongs to the orthorhombic crystal system, meaning its crystals have three unequal axes at right angles to each other. Its crystal structure often forms prismatic or tabular-shaped crystals, occasionally exhibiting striations on their surfaces. These crystalline forms make diaspore visually attractive.

Physical Properties

In terms of physical properties, diaspore has a hardness of 6.5-7 on the Mohs scale. This makes it relatively durable and resistant to scratching but not as hard as minerals like quartz or topaz. Diaspore also has a specific gravity ranging from 3.2 to 3.5, which means it is heavier than an average rock of the same size.

Occurrence and Resources

Diaspore is found in several countries worldwide. Besides its initial discovery in Russia, it has also been found in places like Turkey, Brazil, Hungary, and even the United States. These widespread occurrences make diaspore relatively accessible to collectors and researchers.

References

For more information about diaspore, you can refer to mindat.org, a reliable source for mineral information. The page dedicated to diaspore provides valuable data about its occurrence, physical properties, and locality information. It also features photographs that showcase diaspore's color-changing ability and various crystal forms.

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