Coatings on Minerals
Coatings of elements and solutions on minerals have been utilized to increase the value of colorless and clear quartz, as well as other minerals.
The most common form of coating is vapor deposition, which is what the majority of man-made colored quartz consists of in this day and age. Material treated in this manor has many trade names, like Aqua Aura, Angel Aura, Flame Aura and Opal Aura.
Inside a vacuum, the item to be coated, such as Quartz, is heated to a very high temperature, then a mist of vaporized metal is introduced into the vacuum, resulting in a non-removable bond between the quartz and vaporized metal.
Element = Color of coating
Gold = Blue
Titanium = Multi-colored sheen on white
Indium = Violet
Copper = Orange
It is not only your typical quartz crystal, clear and slender, that can be coated. I want to post a message I received from someone who helped manufacture this material for a large wholesale mineral warehouse in 2004.
When I first started working at this warehouse, one of my co-workers explained what the lab required. For us to hand select each piece to be coated for cracks and weak bonds between the clusters. We would pull flat after flat of quartz clusters, apply pressure to them to check if they were stable enough for the treatment and stockpile those clusters for a shipment to the lab. If the crystals were brittle or had a weak bond, during the heating process, they would shatter, and inside a vacuum, that could lead to the destruction of more quartz crystals. To get the material coated was a per-pound rate, so we were also not sending out any large specimens or clusters. We would find odds and ends of quartz pieces, like faceted quartz pendulums that had fallen off their chains, or funky odd-ball quartz crystals from around the world. In fact, it was the “spirit” quartz from South Africa that got us kicked up into gear. At the best of times, this style of quartz from South Africa was a beautiful purple, sometimes, a pseudo-citrine, and at the worst, colorless and in fact, kind of a grungy gray color. We sent in a selection of this quartz and it came back beautiful, so we kept increasing the order and the amount of colors to choose from, the typical blue, but also, purple, orange and what we called “Opal Aura”, because it would be white with a play of colors over the surface. People went wild for this material, we would make sure to get a large amount processed for the Tucson gem show and during normal times, whenever a new order would come in, it would get picked apart as we were unpacking them. After I quit that job I found over the years more and more stuff was getting sent in for processing, like druzy quartz geodes.
In fact, several different types of material have been treated in this way, the thing to keep in mind is that this coating is non-removable and only surface deep, so if the cluster is broken, chipped or cut, the original interior structure will be unchanged. For this reason, anything cut or faceted with this treatment was surely cut and faceted prior to the treatment.
Another simple form of coating has been around for decades, magnetron ionization. Quartz treated with Titanium or Niobium, this process does not require the quartz to be heated to the extremes of vapor deposition and can be see in quartz and glass spheres with the rainbow sheen held in the pewter/lead wizard hands found in so many mall kiosk stands and incense burning head shops across the world.
Colored Teflon films were used in the past to create something that was called “Jelly Quartz” or “Jello Quartz”, due to the almost candied look to the clusters. Any bright color imaginable was used to coat these crystals, often with several colors used on the same specimen. These items were hard to find in the 1980′s and 1990′s when they were created and the author has not seen one available for nearly a decade.
Aniline Dye is available in every color imaginable and reacts well with many minerals, especially zeolite crystals. Stilbite, Heulandite, Apophyllite and others all welcome the bright colors of aniline dye and make colorful and inexpensive specimens out of the abundant supply of large zeolite clusters from India.