Hair Jewelry
Hair jewelry is jewelry containing or composed of locks of hair. This type of jewelry was popular in the mid-1800's as a remembrance of deceased loved ones.

Hagler, Stanley
Stanley Hagler was a jewelry designer whose pieces were opulent, complex, hand-wired, and usually colorful. Hagler produced pieces from 1953 until 1996. He produced pieces for Lord & Taylor, Bergdorf Goodman, and Saks Fifth Avenue. Hagler's partner, Ian St Geilarm, designed many of the Hagler pieces. After Stanley Hagler's death in 1996, jewelry continued to be produced under the name Stanley Hagler & Company.

Hallmark
A hallmark is an official mark (or a series of marks) made in metal that indicates the fineness of the metal and the manufacturer's mark. For example, a hallmark of 925 indicates 925 parts of gold per 1000 weight. Other hallmarks indicate the maker of the piece and sometimes the year of manufacture. In many countries (like Britain) it is illegal to hallmark metal incorrectly; some countries are notoriously lax in their enforcement of hallmark honesty.

Hammered Metals
Hammered metals have been formed, shaped, or decorated by a metalworker's hammer. The surface of hammered metal is covered with crater-like depressions made by a hammer. Many hammered metals are used in jewelry including gold, silver, brass, aluminum, etc. The pin above is hammered silve

Hardness
Hardness is measured using the Mohs Scale of Hardness. A substance's hardness value indicates the materials resistance to scratching and grades minerals on a comparative scale from 1 (very soft) to 10 (very hard).. In the Mohs scale, a mineral of a given hardness rating will scratch other minerals of the same rating, as well as any minerals of a lower rating. For example, sapphires and rubies have a Mohs rating of 9 and will scratch each other, as well as any mineral with a rating lower than 9. However, they will not scratch diamonds, which are rated 10. The Mohs scale of mineral hardness was devised by the German mineralogist Frederich Mohs (1773-1839) in 1812.
Substance Hardness
Talc 1
Amber, Fingernail, Ivory, Shell, Jet 2.5
Gold 2-3
Bronze, Coral, Pearl 3
Iron 4
Glass 5
Opal 5.5-6.5
Amethyst, Chalcedony, Quartz, Steel (pocket knife) 7
Spinel, Topaz 8
Ruby, Sapphire 9
Diamond 10

Haskell, Miriam
Miriam Haskell (1899-1981) was a costume jewelry designer who designed feminine, intricate jewelry. Haskell frequently used "antique"-gilded surfaces, pearls, intricate beadwork, and naturalistic themes. Miriam Haskell started signing her jewelry in the early 1950's although she began selling jewelry in 1924. Her jewelry is still manufactured and is widely collected.

Hawk's Eye
Hawk's eye is a green, grey or blue variety of quartz that has parallel, fibrous inclusions of crocidolite that give it a greenish cat's eye effect (chatoyancy). This mineral has a silky luster. It looks a lot like Tiger's Eye, and often occurs with it in the same rock, but the internal structure is different.

Heat Treatment
Heat treatment is the heating of stones to a high temperature in order to enhance the color or clarity. For example, blue-green aquamarine becomes blue with heat treatment and brown zircon becomes blue or clear.

Heishi
Heishi (pronounced he-she) is jewelry made from disk-shaped beads of shell (or turquoise, lapis lazuli, and other stones). Each bead begins as a tiny flat piece of shell (or stone). A tiny stringing hole is drilled though the fragment. Many of these jagged pieces are strung together tightly on a wire and are then sanded into evenness using a fine-grained sandstone and then sandpaper. The result is a very smooth strand of disk-shaped beads. This is an ancient form of bead-making developed by the Pueblos of North America.

Helenite
Helenite is a manmade (not natural) green glass that is made from "rock dust" (not volcanic ash) taken from the vicinity of the Mt. St. Helens volcano in Washington state. The dust is fired to 2700 degrees F, forming glass, which is later faceted and used as a gemstone. This glass is sometimes called emerald obsidianite or Mount St. Helens obsidian (but it is not obsidian, which is a natural glass). Helenite is sold as a souvenir of the eruption of Mt. St. Helens on May 18, 1980. The composition of rock from Mt. St. Helens is: Rock from Mt. St. Helens is composed of: silicone 60.50%, aluminum 16.60%, iron 6.02%, calcium 5.36%, sodium 4.18%, manganese 2.59%, potassium 1.20%, titanium .90%, phosphorus .35%, magnesium .12%, strontium .06%, Beryllium .04%, copper .03%, lead .03%, zirconium .02%, chromium .02%, and zinc .02%; the remaining 0.16 percent is sulfur, chlorine, and water.

Heliotrope
Heliotrope (commonly known as bloodstone) is an inexpensive type of chalcedony that is green with red highlights (caused by iron oxide). Heliotrope is porous and relatively soft.

Hemalyke
Hemalyke is a synthetic hematite that is made by grinding up hematite, adding a binder (glue) and then press-molding it. The stone is sometimes faceted. Hemalyke looks very much like natural hematite - it is very difficult to them apart.

Hematite
Hematite (sometimes spelled haematite, and also known as kidney ore) is a lustrous, opaque, blue-black to silvery gray mineral often used in jewelry. Hematite is iron oxide (Fe2O3). Hematite has a hardness of 6.5 and a specific gravity of 4.95 to 5.16. When powdered, hematite is red; when rubbed on a hard stone, it leaves a red streak. Hematite was often used as seal stones, cut as intaglio. It is also used as beads and is faceted, carved or cut as a cabochon for use as a gemstone. The ancient Egyptians carved hematite into scarabs. Hematite is found in England, Mexico, Australia, Brazil, and the Lake Superior region of North America.

Herkimer Diamonds
Herkimer diamonds are clear, lustrous, doubly terminated crystals of quartz - they are not true diamonds. These brilliant stones are also called "Middleville Diamonds" or "Little Falls Diamonds." Herkimer diamonds have a hardness of 7. This stone is found in Middleville and Little Falls, Herkimer County, New York, USA.

Hessonite
Hessonite (also called "cinnamon stone") is a cinnamon-brown to orange gemstone variety of grossular garnet. Hessonite's formula is Ca3Al2Si3O12; manganese that gives it its characteristic brown color. This transparent stone has a hardness of 6.5 - 7 and a specific gravity of 3.6. Hessonite is found in Sri Lanka, Brazil, Madagascar, Canada, and California, USA. This stone is not enhanced.

Hobe
Hobe Cie is a costume jewelry company that was founded by William Hobé in New York in the 1930's. William Hobe had immigrated to the US from France, where his family had made fine jewelry for generations. Hobe jewelry was used in showgirl costumes in the Ziegfeld Follies (Hobe supplied many of the costumes themselves - this was his original business in the US). Florence Ziegfeld (who founded the Ziegfeld Follies) was probably the first person to use the term "costume jewelry." Hobe jewelry was used in many Hollywood movies. Hobe produced very high quality (and very high priced) jewelry for upscale stores, often using semi-precious stones (like turquoise, lapis lazuli, jade, and agate). In the 1940's, the Hobe slogan was "Jewels of legendary splendor." The Hobe company is still producing costume jewelry.

Hook And Eye Clasp
A hook and eye clasp is a simple and ancient jewelry fastener that is composed of a hook and a circular piece that the hook can latch onto. It is used to attach the two ends of a necklace or bracelet.

Howlite
Howlite is a soft, white to gray mineral that takes dye very easily, and can be dyed to imitate turquoise very well (and is sometimes unscrupulously sold as turquoise). Howlite was named for its discoverer, Henry How, a Nova Scotia geologist.

Hyacinth
Hyacinth is a semi-precious stone that is also known as jacinth. it is a lustrous orange-yellow, orange-red, or yellow-brown type of zircon. Hyacinth has a hardness of 7.5 and a specific gravity of 4.65. Sometimes, topaz and grossular garnet of this color are also referred to as hyacinth (this can be very confusing). Hyacinth is mined in Sri Lanka. Even more confusing is the origin of the name, which comes from the Greek hyakinthos, which refers to blue gemstone.

Hyacinth Opal
Hyacinth opal (also known as girasol) is a yellow or orange type of precious opal. In this opal, the play of colors seems to come from within the stone, like a floating light, and seems to follow the light source.