Heartache Stone
Amethyst is a variety of quartz in lilac-violet hues. Interestingly, the beautiful lilac or cherry-blue color of amethyst is due not to impurities of manganese compounds, as previously thought, but to iron ions of different valence and defects (electron-hole centers) in the crystal lattice of the mineral. Crystal lattice defects are deviations from the ideal spatial periodicity in its real structure. And under the influence of the energy of direct sunlight, the ordering of these defects is disturbed and over time amethyst can lose its color and turn into a simple colorless or slightly colored quartz.
Amethyst with uneven coloration and inclusions - "growth zones".
Amethyst is one of three purple minerals traditionally used in jewelry.

Amethysts are characterized by zoning (unevenness) of color, weak dichroism, and the presence of inclusions. The most common inclusions are minerals such as magnetite, goethite, hematite and rutile.

When heated to a temperature of about 250 °, amethyst loses its color, gradually turning into yellow or greenish, and becomes colorless.

When heated to 300-400°C, amethyst turns yellow, orange, or brown, making it similar to another variety of quartz, citrine.

Heating amethyst to 470 - 750 °C produces light yellow, red-brown, green or colorless crystals. In this case, the original color of the crystals can be restored using X-ray irradiation.

Opaque amethyst
There is an interesting legend about amethyst. The god of winemaking Bacchus once took offense at people. They completely stopped reading him. Insulted, Bacchus decided to take revenge on the people: the first person he met would be torn to pieces by lions.

The first was the nymph Amethyst. She went to the temple of the goddess of hunting Diana. When the ferocious beasts pounced on the gentle nymph, she pleaded: "Oh, the beautiful goddess Diana, save me!" Then Diana turned Amethyst into a statue of pure stone. Seeing this miracle, Bacchus regretted his cruelty. He, like blood, poured grape wine into the statue, trying to revive the nymph. But the girl did not come to life. The stone only changed color and became crimson-violet.