Hair Line Finish
Hair line finish is one kind of texture, and it is expressed by countless thin lines that resemble hair.
An official stamp indicates the composition of the metal and its purity.
A hammered finish is a kind of texture.
It is expressed by hammered marks over the surface.
Heating is a treatment to improve the look of a gemstone's color by adding heat to the gem. The following are examples of gemstones improved by heating treatment:
· Ruby, aquamarine, etc. - Removes extra color sharpness
· Tourmaline, sapphire, etc. - Makes the color bright
· Sapphire, etc. - Makes the color darker
· Citrine, etc. - Changes the color tone
Heating is a treatment to change the color of the gemstone with heat. (Example: change from white opal to black with heat)
Heliodor was named from "helios" which means sun in Latin. Heliodor generally crystallizes in hexagonal prisms. Originally, all colorations, from yellow to yellowish green, were referred to as heliodor however recently the yellow variations are called golden beryl or yellow beryl whereas variations that tend towards green are still referred to as heliodor. Heliodor can be irradiated to deepen its color.
[Moh's hardness: 7] [Mineral species: Beryl]
Hemimorphite was named from "hemi," meaning "half," and "morphe," meaning "Shape" in Greek because the shape of both ends of the crystal is different. Usually, it is colorless, but some stone with bright blue is cut and polished into cabochon cut and beads. Green hemimorphite is mined in Mexico and called "azteck stone."
[Moh's hardness: 4.5-5] [Mineral species: Hemimorphite]
This chain gets its namesake from the herringbone (fish bone) that it resembles. The flat texture and slanted parallel chains are the primary identifying features of this chain.
Hinge bracelets are a type of bangle bracelet. This type has a hinge so it can be opened and closed. This design uses spring loaded clasp and clip-like metal fastener.
This type of earring is hoop-shaped. Currently, electroforming technology allows for larger sizes. There are many types of hoop earring material, such as slim and thick wire, hollow wire, and more.
Surface designs may also vary, with roping or knitted designs as just a couple of many examples. Simple "G-type" or "moon-type" designs are popular as well.
It is said that the hope diamond brought misfortune on past owners. It was donated to the Smithsonian Museum in Washington DC where it is currently located. Its color is grayish blue.
HPHT (High Pressure and High Temperature Process)
HPHT is a production method of lab-grown diamonds.
This method is artificially imitating the process of making natural diamonds. Growing time is shorter than the CVD process.
The hydrothermal process is one of the production methods of lab-grown gemstones. This process was developed in 1957 by Bell Laboratory, an American Communication Research Establishment. By putting raw materials and water in an autoclave, lab-grown gemstones will grow under high temperatures and high pressure.
Quarts and emerald can be grown by this process.