Rubies & Sapphires

Schrödinger's gem

What are some rare photos of raw, rough and uncut gemstones?

Rubies and sapphires are both members of the corundum group with the same crystallographic and gemological properties. With the exception of trace elements, the chemistry of rubies and sapphires is also the same. The only real difference between rubies and sapphires is the color. In essence, a red corundum is considered to be a ruby while any other color is considered to be a sapphire. The distinction seems simple, but the determination is not straight forward and there are many borderline stones which may be red to people outside the gem business, but not red enough to satisfy the labs making the final identification.