What an interesting Color. The bible doesn't use the word turquoise very often. This unique color is only mentioned in old testament, and even then it is only mentioned four times. Given what I am about to impart to you, I believe that you will find this to be more than a coincidence.
The fourth son of Israel and the tribe from which Jesus was born is associated with the color turquoise. This color is a mix of blue with a very slight hint of yellow which makes this dynamic shade of green. Therefore, you can gain an understanding of the color from learning what Yellow and Blue represent as well as understanding the Hebrew meaning of the number four. There is a notation of peace and calmness that this color brings which is associated with the color green. There is a deep revelation hidden in it, and the consciousness of God is represented.
Because this color is associated with Judah then it can mean reigning, ruling, or authority. Judah derives from the Hebrew word Yadah meaning to praise, to thank, to confess, or to raise up holy hands. It can also be a play on words for the Hebrew word Yada, which means to know, or to have knowledge of. That correlates with the color yellow which represents intelligence, and way of thinking, or intellectual pride. An interesting factor I discovered is that Turquoise is also associated with the color green, and the number four. Green represents peace, calmness, new life and growth. To the same extent the number four in Hebrew represents Government, creation, Kingdom, a doorway, and a portal to an open Heaven. All of these factors apply to the color turquoise.
The negative aspects of this color could represent sickness, sorrow, depression, anxiety. If someone were to say it was a dark turquoise color that would indicate that the dream is from the enemy in origin which insinuates being full of false light or full of darkness. It may also represent coming under judgment.
I pray that this was a blessing to you. Have a blessed day.