What crystals (or Gem Stones) corespond with colors of the rainbow?

Rainbow colors are red, orange, yellow, green, blue, indigo, and violet, what are the gems That Are these colors are associated. I have;
red=ruby
green=emerald
blue=saphire
yellow=topaz/yellow diamond
violet= amethyst
orange=?
indigo=?

saphire/ruby are the same mineral (corundum), and can show a wide array of colors.
Here’s an example:

http://www.campuscomm.k12.de.us/gemstone/sapphire/sapphire.jpg

Just as colored quartz is called amethyst or citrine. Topaz also comes in a lot of colors, most commonly clear.

Personally, I would place classic blue saphires as indigo, and blue topaz as the blue.

Garnet also makes a good red, but some varieties can be green (look up uvarovite)
Vanadite or realgar make nice oranges.
I’ve seen very nice yellow apatite crystals
peridot is a light green, or green tourmaline
and I already mentioned blue topaz and saphire for blue/indigo.
for a light purple, kunzite is a nice alternative.

Amethyst Model Casper WY 82601 – Obeo Virtual Tour 496734