Mine Every Monday - Sapphire

What I want to introduce to you today is the big caste of the corundum family - sapphire.

The sapphire itself is composed of aluminum oxide (Al2O3), the same composition as the rust scraped from the aluminum window frames used in classrooms as a child.

It is also alumina, but only with perfect α crystal form can it be called "corundum", and only corundum with very high purity can be called "gem".
The following picture is simple for everyone to explain.

In α-crystalline alumina (hereinafter referred to as α-alumina), oxygen ions (O2-) are closely packed hexagonally, and aluminum ions (Al3+) are symmetrically distributed in the center of octahedral ligands surrounded by oxygen ions (as shown in the figure below). ), and therefore, α-alumina has a very high melting point, boiling point and hardness, and is an important material for bearings or abrasives.

The blue color of sapphire comes from the high purity of corundum mixed with some ferric oxide and titanium dioxide.

Interestingly, the so-called "sapphire" is generally considered to be a "blue gemstone", but in mineralogy, sapphire is defined as "a general term for corundum other than ruby."
It means "in the corundum family, as long as it is not a ruby, it is called a sapphire."
So the so-called "sapphire" is not only blue.

There are also yellow sapphires with nickel oxide mixed in crystals.

Or green sapphires containing iron, cobalt and vanadium.

Among the "non-blue" sapphires, the most valuable is a pinkish-orange sapphire called "Padparadscha", which is transliterated in Chinese as padparadscha, or translated as "lotus sapphire", "lotus corundum" ".
Because the word "padparacha" means lotus in Ceylon.
Padparadscha also has several colors, but they are all between pink-orange to orange-pink. The ideal situation is naturally half and half of pink and orange, but this standard padparadscha is too rare.
Therefore, pink and orange account for 30% to 70% of the color of the whole gem, and those without other variegated colors can be called padparadscha. Padparadscha is also the national stone of the gem kingdom of Sri Lanka.

In addition to padparadscha, which is too rare and expensive, the highest price in the sapphire family is naturally sapphire.
In addition to size, sapphire is priced based on color, of course.
Generally speaking, the color saturation is high, rich and uniform, and it is the top grade, such as the most well-deserved royal blue.

In recent years, there has been a kind of "Cornflower Blue" that is prolific in Kashmir, India.

Compared with the calm and extravagance of royal blue, cornflower blue has a brighter fire, and its overall temperament is more eye-catching than royal blue.
If Royal Blue is likened to a wealthy and wealthy wife who made a fortune from scratch with her husband, then I think Cornflower Blue is a lively, pretty, yet confident eldest lady who has been pampered by several generations of family backgrounds.

Sapphire is also a good material in the industrial field because of its impressive hardness (9 on the Mohs scale, only diamonds can scratch it).

The production of natural sapphire is limited, so humans have developed methods for synthesizing ruby and sapphire in the laboratory.
The most common and fastest method is the "bubble method". In simple terms, it is to provide a crystal nucleus and a solution, and then gradually cool down to allow the gem crystal to grow and thrive in the solution.
This kind of synthetic sapphire is almost the same as natural sapphire in transparency, hardness, melting point, etc.

This kind of industrial synthetic sapphire is widely used in blue LED (semiconductor GaN/Al2O3 light-emitting diode), large-scale integrated circuit SOI and SOS and superconducting nanostructure thin film, and Apple is also the first in the lens of iPhone 5. Started using sapphire glass lenses.
Thanks to the scratch resistance of sapphire glass, sapphire glass is also used for the cover of the fingerprint recognition module of the iPhone 5s and the screen protection glass of the Apple Watch.

Alumina, the constituent of sapphire, can actually be found in large quantities in the roadside soil.
The difference between "sapphire" and "mud" can be caused by the difference in the generation environment.
Sometimes when we look at the sapphire in our hand, we can’t help but think, maybe we often feel that we are in a high-pressure environment like swimming against the current, and if we relax a little, we will be slammed downstream, and we envy the carefreeness of others.

But maybe, this is the necessary experience for you to become a sapphire.