Blue quartz contains inclusions of fibrous magnesio-riebeckite or crocidolite.
Additionally, there is a rare type of pink quartz (also frequently called crystalline rose quartz) with color that is thought to be caused by trace amounts of phosphate or aluminium. The color in crystals is apparently photosensitive and subject to fading. The first crystals were found in a pegmatite found near Rumford, Maine, US and in Minas Gerais, Brazil.
Rose quartz is a type of quartz which exhibits a pale pink to rose red hue. The color is usually considered as due to trace amounts of titanium, iron, or manganese, in the material. Some rose quartz contains microscopic rutile needles which produces an asterism in transmitted light. Recent X-ray diffraction studies suggest that the color is due to thin microscopic fibers of possibly dumortierite within the quartz.
Inclusions of the mineral dumortierite within quartz pieces often result in silky-appearing splotches with a blue hue, shades giving off purple and/or grey colors additionally being found. "Dumortierite quartz" (sometimes called "blue quartz") will sometimes feature contrasting light and dark color zones across the material. Interest in the certain quality forms of blue quartz as a collectible gemstone particularly arises in India and in the United States.
Milk quartz or milky quartz is the most common variety of crystalline quartz. The white color is caused by minute fluid inclusions of gas, liquid, or both, trapped during crystal formation, making it of little value for optical and quality gemstone applications.
Smoky quartz is a gray, translucent version of quartz. It ranges in clarity from almost complete transparency to a brownish-gray crystal that is almost opaque. Some can also be black. The translucency results from natural irradiation creating free silicon within the crystal.
As of OS X El Capitan, Quartz Extreme is enabled on all supported Macs.
Mac OS X v10.2 introduced Quartz Extreme: graphics processor (GPU) acceleration for the Quartz Compositor. With Quartz Extreme, far fewer central processor (CPU) cycles are needed for scene composition. Instead, the Quartz Compositor encapsulates each rendered backing store in an OpenGL texture map or surface. It then directs the GPU to compose the surfaces and maps to provide the final image, which is delivered to the frame buffer.
Quartz 2D is the primary two-dimensional (2D) text and graphics rendering library: It directly supports Aqua by displaying two-dimensional graphics to create the user interface, including on-the-fly rendering and anti-aliasing. Quartz can render text with sub-pixel precision; graphics are limited to more traditional anti-aliasing, which is the default mode of operation but can be turned off. In Mac OS X 10.4 Tiger, Apple introduced Quartz 2D Extreme, enabling Quartz 2D to offload rendering to compatible GPUs. However, GPU rendering was not enabled by default due to potential video redraw issues or kernel panics. As of Mac OS X v10.5 Quartz 2D Extreme has been renamed to QuartzGL. However, it still remains disabled by default, as there are some situations where it can degrade performance, or experience visual glitches; it is a per-application setting which can be turned on if the developer wishes.
Clock quartz crystals are manufactured in an ultra-clean environment and protected by an inert ultra-high-vacuum environment in hermetically sealed containers. Still the frequency of a quartz crystal can slowly change over time causing the frequency to increase or decrease over time. The effect of ageing is much smaller than the effect of frequency variation caused by temperature changes and manufactures can estimate its effects. Generally, the ageing effect eventually decreases the frequency. Factors that can cause a small frequency drift over time are stress relief in the mounting structure, loss of hermetic seal, contaminations contained in the crystal lattice, moisture absorption, changes in or on the quartz crystal, severe shock and vibrations effects, exposure to very high temperatures. Crystal aging tends to be logarithmic meaning the maximum rate of change of frequency occurs immediately after manufacture and decays thereafter. Most of the aging will occur within the first year of the crystals service life. Crystals do eventually stop aging (asymptotically), but it can take many years. Movement manufacturers can pre-age crystals before assembling them into clock movements. To promote accelerated ageing the crystals are exposed to high temperatures. If a crystal is pre-aged, the manufacturer can measure its ageing rates (strictly, the coefficients in the ageing formula) and have a microcontroller calculate out the corrections over time. The initial calibration of a movement will stay accurate longer if the crystals are pre-aged. The advantage would end after subsequent regulation which will, reset any cumulative aging error to zero. A reason more expensive movements tend to be more accurate is that the crystals are pre-aged longer and selected for better ageing performance. Sometimes individual crystals after pre-ageing are hand selected for high-accuracy movement performance.
The Quartz Compositor is the compositing engine used by macOS. In Mac OS X Jaguar and later, the Quartz Compositor can use the graphics accelerator (GPU) to vastly improve composition performance. This technology is known as Quartz Extreme and is enabled automatically on systems with supported graphics cards.
The Oklahoma State Regents for Higher Education operates the Quartz Mountain Resort. It includes a 118-room lodge, a guesthouse, cabins, bunkhouse, RV hookups and primitive campsites.
A developer tool called Quartz Composer Visualizer was released with Quartz Composer 3.0 that allows compositions to be rendered across multiple screens on a single machine, or even spanned across several machines and displays.
In 1974 Omega introduced the Omega Marine Chronometer, the first watch ever to be certified as a marine chronometer, accurate to 12 seconds per year using a quartz circuit that produces 2,400,000 vibrations per second. In 1976 Omega introduced the Omega Chrono-Quartz, the world's first analogue-digital chronograph, which was succeeded within 12 months by the Calibre 1620, the company's first completely LCD chronograph wristwatch.
As a result of the economic turmoil that ensued, many once-profitable and famous Swiss watch houses became insolvent or disappeared. This period of time completely upset the Swiss watch industry both economically and psychologically. During the 1970s and early 1980s, technological upheavals, i.e. the appearance of the quartz technology, and an otherwise difficult economic situation resulted in a reduction in the size of the Swiss watch industry. Between 1970 and 1983, the number of Swiss watchmakers dropped from 1,600 to 600. Between 1970 and 1988, Swiss watch employment fell from 90,000 to 28,000.
The drawing model utilized by Quartz 2D is based on PDF specification 1.4. Drawing takes place using a Cartesian coordinate system, where text, vectors, or bitmap images are placed on a grid. However, drawing output is not sent directly to the output device. Quartz 2D uses graphics contexts, environments in which drawing takes place. Each graphics context defines how the drawing should be presented: in a window, sent to a printer, an OpenGL layer, or off-screen. Each context rasterizes the drawing at the desired resolution without altering the data that defines the drawing. Thus, contexts are the mechanism by which Quartz 2D employs resolution- and device-independence. For example, a window context may rasterize an object to the appropriate screen resolution to create actual graphics on the display. The same object can be sent to a printing context at a much higher resolution. This permits the same graphics commands to yield output on any device using the most appropriate resolution.
Despite these dramatic advancements, the Swiss hesitated in embracing quartz watches. At the time, Swiss mechanical watches dominated world markets. In addition, excellence in watchmaking was a large component of Swiss national identity. From their position of market strength, and with a national watch industry organized broadly and deeply to foster mechanical watches, many in Switzerland thought that moving into electronic watches was unnecessary. Others outside of Switzerland, however, saw the advantage and further developed the technology. By 1978, quartz watches overtook mechanical watches in popularity, plunging the Swiss watch industry into crisis while at the same time strengthening both the Japanese and American watch industries. This period of time was marked by a lack of innovation in Switzerland at the same time that the watch-making industries of other nations were taking full advantage of emerging technologies, specifically quartz watch technology, hence the term "quartz crisis".
Outside of Switzerland, the crisis is often referred to as the "quartz revolution", particularly in the United States where many American companies had gone out of business or had been bought out by foreign interests by the 1960s. When the first quartz watches were introduced in 1969, the United States promptly took a technological lead in part due to microelectronics research for military and space programs. It was American companies like Texas Instruments, Fairchild Semiconductor, and National Semiconductor, who started the mass production of digital quartz watches and made them affordable. It did not remain so forever; by 1978 Hong Kong exported the largest number of electronic watches worldwide, and US semiconductor companies came to pull out of the watch market entirely. With the exception of Timex and Bulova, the remaining traditional American watch companies, including Hamilton, went out of business and sold their brand names to foreign competitors; Bulova would ultimately sell to the Japanese-owned Citizen in 2008.
Quartz 2D expands the drawing functions associated with QuickDraw. The most notable difference is that Quartz 2D eliminates output device and resolution specificity.
Other birefringent materials can be used in place of quartz in the above designs.