Zircon crystals synthesized in a ..

Upon turning his/her attention to thegem, what meets the eye is globs of dirt and grime surrounding thegem, and in most cases startlingly visible "crud"

The crystal structure of zircon is tetragonal ..

20 Oct 2015: Carbon isotopes that may point to life have been found in 4.1 billion-year-old zircon.

Analysis of silica fume produced by zircon ..

There are three major methods used today to make synthetic gem minerals commercially. In the first, the flame-fusion process, powdered oxide are melted in a furnace by a high-temperature flume and accumulated in hardened form as cooling and crystallization take place. By this technique, corundum and a number of other gem minerals are made, including rutile, strontium titanate and spinel, as well as the non gem minerals cadmium tungstate and calcium tungstate (synthetic scheelite). By the second method, a hydrothermal process, quartz, opal, beryl (emerald) corundum and fluorite are crystallized from solution under conditions of high temperature and pressure, by dissolving fragments of the mineral and re-depositing it as transparent, gem-quality crystals. In laboratory experiments, most of the important gem minerals have been produced by crystallization from solution (hydrothermal methods); however, only those mentioned above are produced on a commercial scale. The third method is termed flux growth, and this is a means by which under high temperature and pressure conditions, materials are dissolved in a melt in which they are more readily soluble than in water. A modification of the melt-growth technique is the Czochralski or crystal-pulling technique. It is by this method that Chatham and Gilson have made their synthetic emeralds, and it is also the method by which Chatham and Kashan are making synthetic rubies. Synthetic alexandrites and sapphires are also flux grown.

Crystal Color Wheel and Elements of Color

Metal sulfides are of interest for a wide variety of applications, including use as hydrodesulfurization catalysis, and as photovoltaic materials. Many transition metal sulfides have complex structures due to the combination of variable oxidationstate on the transition metal, and the fact that sulfur can exist as S2 or S3 units in addition to isolated monoatomic anions. Some of these compounds are only stable at low temperatures, converting to simpler, more thermodynamically stable phases at higher temperatures. This makes synthesis somewhat difficult.

The oldest mineral (zircon) is foundin sedimentary rock in Australia and is 4.2 eons old.
What you are seeing is the

Oceanography: Oceans - Seafriends

Scharer, U. and C. J. Alegre (1985). "Determination of the age of the Australian continent by single-grain zircon analysis of Mt Narryer metaquartzite." Nature 315(6014): 52-55.

Our synthetic gemstone guide covers many examples ..

Molten metals have been used as solvents for the growth of a variety of compounds, ranging from large single crystals of silicon to exploratory synthesis of new intermetallic materials. Reactions in metal fluxes can be carried out at lower temperatures than those typically required for traditional solid state synthesis, allowing for the formation of metastable or kinetically stabilized products. Flux reactions are also solution-state reactions, allowing for crystal growth with slow cooling of the melt.

Yin said, What should make the technology commercially attractive is that iron oxide is cheap, non-toxic and available in plenty.

Investigation of single crystal zircon, (Zr,Pu) ..

Zircon is a gem and industrial mineral. Its name is of obscure origin, but is possibly derived from the Persian for “gold colored.” It is also known as jacinth, or hyacinth, and jargoon.

Zircon is usually found as reddish- to yellowish-brown granules, but occasionally it is green or gray, or may even be colorless. It ranges from dull and opaque to transparent with a high adamantine luster. The latter variety is of gemstone quality. A long-standing practice in Southeast Asia has been to heat zircon river pebbles in primitive kilns, sometimes several times over, in order to change their natural red or orange color to golden yellow or pastel blue, or make them perfectly clear and colorless. Today Bangkok has become a high-tech center for heat enhancement and zircon cutting.

Hard, heavy, and brittle, zircon crystals consist of short tetragonal (four-sided) prisms, terminating in pyramids at both ends. With a very high refractive index and optical dispersion that approaches that of a diamond, a zircon can rival the fiery brilliance and color play of that most fabled of precious stones.

Since ancient times high-quality zircon has been used as an ornamental gemstone. Carved examples have been recovered from early archaeological sites; jacinth is mentioned in the Bible (Exodus 28:19) as one of the stones adorning the high priest’s breastplate; and faceted zircons have been a feature of South Asian jewelry for centuries. In a modern application, zirconium metal derived from non-gem quality zircon is used in space-age alloys.

By no means a rare mineral, zircon occurs worldwide in igneous rocks or concentrated in alluvial deposits in the form of small grains. Gemstone varieties are found primarily in Cambodia, Burma, Thailand, Vietnam, and Sri Lanka, and to a lesser extent in Russia and France, New Zealand, and Australia, Tanzania, and the Malagasy Republic. Minuscule zircon crystals are found in beach sands in North Carolina and Florida.

Renowned in medieval times as a palliative, zircon was reputed to help women in childbirth. Most of the stone’s manifold powers, however, were specifically reserved for men. Thus zircon amulets protected the stronger sex against bad dreams and evil spirits, stimulated male appetites yet suppressed male fat, fortified men’s hearts and bodies, lulled them to sleep, and banished their sadness.