Ruby and Sapphire

Although I'm not conversant with jewelry, I know ruby and sapphire.Basically, rubies are red, and sapphires are blue.

However, I didn't know the fact that both rubies and sapphires are made of the same ore called 'corundum.'

Corundums have the highest hardness next to diamonds, and their colors change depending on impurities (metal ions).

When chromium is contained as an impurity, the corundum will become red, and the jewel is called ruby.

Also, other corundums that are not changed to red are called sapphires.

Therefore, there are sapphires that the color is yellow, orange, green or pink.

ルビーとサファイア

私は宝石にあまり詳しくありませんが、ルビーとサファイアは知っています。

基本的にルビーは赤色の宝石で、サファイアは青色の宝石です。

しかし、ルビーとサファイアが同じ「コランダム」と呼ばれる同じ鉱石だとは今日まで知りませんでした。

コランダムはダイアモンドに次ぐ硬度を持つ鉱石で、不純物（金属イオン）によってその色が変化します。

不純物としてクロムが混ると赤くなり、ルビーと呼ばれます。

そして赤色以外のコランダムがサファイアと呼ばれます。

このため、黄色やオレンジ、グリーン、ピンクなどの色を持つサファイアが存在します。

• Although I'm not conversant with jewelry, I know ruby and sapphire.
• Although I'm not conversant with jewelry, I do know ruby and sapphire.

  "Do" is not essential, but "although" sets up a contrast, and so "do" emphasizes the distinction. A small point: ruby and sapphire are gemstones, but are not yet jewellery until they are "set" within metal.

• Basically, rubies are red, and sapphires are blue.
• Basically, rubies are red, and sapphires are blue.

  and I feel like teaching a small rhyme to you ;)

• However, I didn't know the fact that both rubies and sapphires are made of the same ore called 'corundum.'
• However, I didn't know the fact that both rubies and sapphires are made of the same ore called 'corundum.'

  "ore" is used for metals before they are reduced: e.g. bauxite is an Aluminum (Al) ore, Galena is a lead (Pb) ore. Here, I think you want to use the word "material" or "substance."

• Corundums have the highest hardness next to diamonds, and their colors change depending on impurities (metal ions).
• This sentence is perfect! No correction needed!

• When chromium is contained as an impurity, the corundum will become red, and the jewel is called ruby.
• When With chromium is contained as an impurities, the corundum will become red, and the jewel is called ruby.

  You've literally translated the "が入っている" syntax here.

• Also, other corundums that are not changed to red are called sapphires.
• Also, other corundums that are not changed to red are called sapphires.

  "Other" limits the corundums to which this name change would apply. You seem to want to mean that all non-red corundums are sapphires.

• Therefore, there are sapphires that the color is yellow, orange, green or pink.
• Therefore, there are sapphires that the color is are yellow, orange, green, or pink.

  "Therefore" is not quite right, because it is used when the following statement follows as a logical or consequence from the previous. So the statement that "non-red corundums are called sapphires" gives no specific information about the possible colors they could have, except that they are not red.

良くできたよ！

• Ruby and Sapphire
• This sentence is perfect! No correction needed!

• Although I'm not conversant with jewelry, I know ruby and sapphire.
• Although I don't know much about jewelry, I know about rubies and sapphires.

• Basically, rubies are red, and sapphires are blue.
• This sentence is perfect! No correction needed!

• However, I didn't know the fact that both rubies and sapphires are made of the same ore called 'corundum.'
• However, I didn't know the fact that both rubies and sapphires are made of the same ore called 'corundum.'

• Corundums have the highest hardness next to diamonds, and their colors change depending on impurities (metal ions).
• Corundum has the highest hardness next to diamonds, and their colors change depending on the impurities (metal ions).

• When chromium is contained as an impurity, the corundum will become red, and the jewel is called ruby.
• With chromium impurities, the corundum will become red, and the jewel is called a ruby.

• Also, other corundums that are not changed to red are called sapphires.
• Also, the other corundums that are not changed to red are called sapphires.

• Therefore, there are sapphires that the color is yellow, orange, green or pink.
• Therefore, there are sapphires that are yellow, orange, green or pink.

When I read the title, I thought you were going to write about the Pokemon games 'Ruby' and 'Sapphire', haha