Search results
Results from the WOW.Com Content Network
The ideal grade, called "Deep Siberian", has a primary purple hue of around 75–80%, with 15–20% blue and (depending on the light source) red secondary hues. " Rose de France" is defined by its markedly light shade of the purple , reminiscent of a lavender / lilac shade.
The term porphyry is from the Ancient Greek πορφύρα (porphyra), meaning "purple". Purple was the colour of royalty, and the Roman "imperial porphyry" was a deep purple igneous rock with large crystals of plagioclase. Some authors claimed the rock was the hardest known in antiquity.
As a result of this phenomenon, a multitude of colors have been observed in various specimens: shades of purple, violet, indigo, blue, cyan, green, yellow, orange, red and brown. After heating, tanzanite becomes dichroic. The dichroic colours range from violet through bluish-violet to indigo and violetish-blue to blue.
It is a mixture of amethyst and citrine with zones of purple and yellow or orange. Almost all commercially available ametrine is mined in Bolivia. The colour of the zones visible within ametrine are due to differing oxidation states of iron within the crystal.
Every color of the rainbow in various shades is represented by fluorite samples, along with white, black, and clear crystals. The most common colors are purple, blue, green, yellow, or colorless. Less common are pink, red, white, brown, and black.
Color Lapis lazuli seen through a microscope (x240 magnification) The intense blue color is due to the presence of the trisulfur radical anion (S •− 3) in the crystal. The presence of disulfur (S •− 2) and tetrasulfur (S •− 4) radicals can shift the color towards yellow or red, respectively.
Topaz is often treated with heat or radiation to make it a deep blue, reddish-orange, pale green, pink, or purple. [8] Topaz is a nesosilicate mineral, and more specifically, an aluminosilicate mineral. [9] It is one of the hardest naturally occurring minerals and has a relatively low index of refraction.
The amethyst is a brilliant transparent stone of a purple colour and varies in shade from violet purple to rose. There are two kinds of amethysts: the oriental amethyst, a species of sapphire that is very hard (cf. Heb., hlm ), and when colourless is almost indistinguishable from the diamond .
Piemontite occurs as small, reddish-black, monoclinic crystals in the manganese mines at San Marcel, near Ivrea in Piedmont, and in crystalline schists at several places in Japan. The purple color of the Egyptian porfido rosso antico is due to the presence of this mineral.
Jadeite's color commonly ranges from white through pale apple green to deep jade green but can also be blue-green (like the recently rediscovered "Olmec Blue" jade), pink, lavender and a multitude of other rare colors.