Amethyst is a violet variety of quartz. The name comes from the Koine Greek αμέθυστος amethystos from α- a-, "not" and μεθύσκω (Ancient Greek) methysko / μεθώ metho (Modern Greek), "intoxicate", a reference to the belief that the stone protected its owner from  drunkenness. Ancient Greeks wore amethyst and carved drinking vessels from it in the belief that it would prevent intoxication. Amethyst, a semiprecious stone, is often used in jewelry and is the traditional birthstone for February. Structure
Amethyst is a purple variety of quartz (SiO2) and owes its violet color to irradiation, impurities of iron and in some cases other transition metals, and the presence of other trace elements, which result in complex crystal lattice substitutions. The hardness of the mineral is the same as quartz, thus making it suitable for use in jewelry. Hue and tone
Amethyst occurs in primary hues from a light lavender or pale violet, to a deep purple. Amethyst may exhibit one or both secondary hues, red and blue. High quality amethyst can be found in Siberia, Sri Lanka, Brazil, Uruguay, and the Far East. The ideal grade is called "Deep Siberian" and 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.
One American survived the infection in 1978 and one individual from Mexico in 2003. In 2013, two children survived and recovered from primary amoebic meningoencephalitis after treatment with miltefosine. In 2016 after treatment that included miltefosine, another child became the fourth person in the United States to survive Naegleria fowleri infection. Society and culture
Availability
Since 2017 Miltefosine is commercially available in the United States through Profounda. Previously one could only get it from the CDC for emergency use under an expanded access IND protocol for treatment of free-living amoeba (FLA) infections: primary amoebic meningoencephalitis caused by Naegleria fowleri and granulomatous amoebic encephalitis caused by Balamuthia mandrillaris and Acanthamoeba species. Miltefosine is almost exclusively produced by Profounda, a private pharmaceutical company. Economics
In the developing world a course of treatment costs US$65 to $150. In the developed world treatment may be 10 to 50 times greater. Further research
It is active against some bacteria and fungi, as well as human trematode Schistosoma mansoni and the snail that spreads it Biomphalaria alexandrina. Antiprotozoal and antifungal activities
Miltefosine is being investigated by researchers interested in finding treatments for infections which have become resistant to existing drugs. Animal and in vitro studies suggest it may have broad anti-protozoal and anti-fungal properties:

Animal studies suggest miltefosine may also be effective against Trypanosoma cruzi, the parasite responsible for Chagas disease. Several studies have found the drug to be effective against types of fungus: Cryptococcus neoformans, Candida, Aspergillus and Fusarium.