Hallmarks

Jewellery (Jewelry in American spelling) comprises ornamental objects worn by persons, typically made with gems and precious metals. Costume jewellery is made from less valuable materials. However, jewellery can and has been made out of almost every kind of material. The word is derived from the word "jewel", which was anglicised from the Old French "jouel" in around the 13th century. Further tracing leads back to the Latin word "jocale", meaning plaything. Some cultures have a practice of keeping large amounts of wealth stored in the form of jewellery. A hallmark is an official marking made by a trusted party, usually an assay office, on items made of precious metals (Platinum, Gold and Silver) that guarantees a certain purity of the metal. This should not be confused with a marking, often just a number such as 925, which is done voluntarily by the manufacturer, and unfortunately does not always reflect the true purity of the metal. A hallmark is only applied after the item has been assayed to determine its purity. Often the hallmark is made up of several elements including: the type of metal, the maker and the year of the marking. History of hallmarking Hallmarking may have begun as long ago as the sixth century AD. Byzantine silver from this time has a system of five marks which have not been completely deciphered. Hallmarking is Europe's earliest form of consumer protection. Hallmarking probably started in France, the standard for silver being established in 1260, but the first town mark was established in 1275. In 1300, King Edward I of England enacted a statute ordering that all silver articles must meet the Sterling silver standard (92.5% pure silver), and should be assayed by 'guardians of the craft', who would then mark the item with a leopard's head. In 1327, King Edward III of England granted a charter to the Worshipful Company of Goldsmiths (more commonly known as the Goldsmiths' Company), marking the beginning of the Company's formal existence. In 1355, individual maker marks were introduced in France, which was mirrored in England in 1363, adding accountability to the two systems. In 1427, the date letter system was established in France, allowing the accurate dating of any hallmarked piece. In 1478, the Assay Office was established in Goldsmiths' Hall. At this time, the date letter system was introduced in England. In 1697, a higher standard of silver, known as the Britannia standard (95.8% silver) was made compulsory in England to protect the new coinage which was being melted down by silversmiths for the silver. The Sterling standard was restored in 1720. In 1975, the 1973 Hallmarking Act was enacted, introducing Platinum marking. All four remaining assay offices finally adopted the same date letter sequences. The latest changes in 1999 were made to the UK hallmarking system to bring the system closer into line with the European Union (EU). International hallmarking has been plagued by difficulties, because even amongst countries which implement hallmarking, standards and enforcement varies considerably, making it difficult for one country to accept another's hallmarking as equivalent to its own. Modern hallmarks United Kingdom hallmarks Pictured here are the assay office marks - from left to right, the leopard's head of London, the anchor of Birmingham, the Yorkshire rose of Sheffield, and the castle of Edinburgh. As it now stands, the compulsory part of the UK hallmark consists of the sponsor or maker's mark, the assay office mark, and the standard of fineness (in this case silver, 925 parts in 1000). These are shown in the top of the two example hallmarks. The bottom example shows the extra marks that can also be struck, the lion passant, indicating Sterling silver, the date mark (lowercase a for '2000'), and in this example, the 'Millennium mark', which was only available for the years 1999 and 2000. The bottom example bears the Yorkshire rose mark for the Sheffield Assay Office. Vienna Convention hallmarks Marking techniques Punching Traditionally, the hallmarks are 'struck' using steel punches. Punches are made in different sizes, suitable for tiny pieces of jewellery to large silver platters. Punches are made in straight shank or ring shank, the former for normal punching with a hammer, and the later used with a press to mark rings. The problem with traditional punching is that the process of punching displaces metal, causing some distortion of the article being marked. This means that re-finishing of the article is required after hallmarking. For this reason, and that off-cuts from sprues are often used for assay, many articles are sent unfinished to the assay office for assay and hallmarking. Laser marking A new method of marking using lasers is now available, which is especially valuable for delicate items and hollowware, which would be damaged or distorted by the punching process. Laser marking also means that finished articles do not need to be re-finished. Laser marking works by using high power lasers to evaporate material from the metal surface. Two methods exist, 2D and 3D laser marking. 2D laser marking burns the outline of the hallmarks into the object, while 3D laser marking better simulates the marks made by punching. Also see Silver Sterling Silver Gems Index

This article is licensed under the GNU Free Documentation License. It uses material from the Wikipedia article Hallmark

Jewish Jewelry - Sapphires

Sapphire

Sapphire (from Hebrew: ספּיר Sapir) is the single-crystal form of aluminum oxide (Al2O3), a mineral known as corundum. It can be found naturally as gemstones or manufactured in large crystal boules for varied applications, including infrared optical components, watch faces, high-durability windows, and wafers for the deposition of semiconductors such as GaN nanorods.

The corundum group consists of pure aluminum oxide. Trace amounts of other elements such as iron, titanium and chromium give sapphires their blue, yellow, pink, purple, orange or greenish color. Sapphire includes any gemstone quality varieties of the mineral corundum except the fully saturated red variety, which is instead known as ruby.

Historical and cultural references

According to Rebbenu Bachya, the word "Sapir" in the verse Exodus 28:20 means "Sapphire" and was the stone on the Ephod representing the tribe of Issachar. However, this is disputed as the sapphire of the Bible was likely lapis lazuli (Texas Natural Science Center, 2006).

Also see Jewish Jewelry

Sapphires have an esteemed history. Tradition holds that the tablets containing the Ten Commandments were composed of sapphire, so strong that a hammer swung against them would be smashed to pieces.

Supernatural powers were attributed to gems in India. One way this was manifested was the interdependence between gems and planets. Ruby, associated with the Sun, was the Lord of Gems, for the Sun lorded over all the planets. Blue sapphire is associated with Saturn (Wojtilla, 1973), yellow sapphire with Jupiter.

Natural Sapphire

Although blue is considered the normal color for sapphire, it is found in the full range of spectral colors as well as brown, colorless, grey and black. Any sapphire other than blue or fully saturated red (ruby) is considered a fancy color sapphire.

Blue Sapphire

Various shades of blue result from titanium and iron inclusions within the aluminum oxide crystal lattice. Some stones are not well saturated and show tones of gray. It is common to bake natural sapphires to improve color. This is usually done by heating the sapphires to temperatures of up to 1800°C for several hours, or by heating in a nitrogen deficient atmosphere oven for 7 days or more. On magnification the silk due to included rutile needles are visible. If the needles are unbroken, then the stone was not heated. If the silk is not visible then the stone was heated adequately. If the silk is partially broken then a process known as low tube heat was used. Low tube heat is the process where the rough stone is heated to 1300 °C for 20 to 30 minutes over charcoal. This takes out any gray or brown in the stone and improves color saturation.

Fancy color sapphire

Purple sapphires are lower in price than blue ones. These stones contain the trace element vanadium and come in a wide variety of shades. Yellow and green sapphires have traces of iron which gives them their color. Pink sapphires have a trace element of chromium and the deeper the color pink the higher the value as long as the color is going toward red of rubies.


Color change sapphire

Color shift sapphires are blue in outdoor light and purple in indoor light. Color changes may also be pink in daylight to greenish in fluorescent light. Some stones shift color well and others only partially, in that some stones go from blue to blue purple. White sapphires usually come out of the ground as light gray or brown and are then heated to make them clear. However in very rare circumstances they will be


Star sapphire

A star sapphire is a type of sapphire that exhibits a star-like phenomenon known as asterism. Star sapphires contain intersecting needle-like inclusions (often the mineral rutile) that cause the appearance of a six-rayed 'star'-shaped pattern when viewed with a single overhead light source. Twelve-ray stars are also found, but are less common.

A "star sapphire" ring with two diamonds on a silver band. The value of a star sapphire depends not only on the carat weight of the stone but also the body color, visibility, and intensity of the star.

Treatments

Some sapphires are heat-treated or otherwise enhanced to improve their appearance and color, though some people object to such practices and prefer natural untreated stones. Treated stones tend to be darker than untreated stones and the treatment process causes changes to the internal structure that are generally easily detected.


Mining

Sapphires are mined from alluvial deposits or from primary underground workings. Historically, most sapphires have been mined in Sri Lanka, Madagascar and Myanmar. Australia leads the world in sapphire production (as of 1987) specifically from basalt derived placer deposits in Queensland and New South Wales. Pakistan, Afghanistan, India, Tanzania and Kenya also produce sapphires. The US state of Montana has produced sapphires from the Yogo Gulch deposit near Helena. Gem grade sapphires and rubies are also found in and around Franklin, North Carolina, USA. Several mines are open to the public.

Top-quality sapphires are rare, Sapphires, call them gemstones of the sky though we may, lie well hidden in just a few places, and first have to be brought to light through hard work.

• Sapphire is the birthstone associated with September.
• The 45th wedding anniversary is known as the sapphire anniversary.
  

This article is licensed under the GNU Free Documentation License. It uses material from the Wikipedia article Sapphire.

The History of Jewelry: Sapphires

<-- Return to MileChai Jewish Jewelry