The price that a ruby will fetch is determined by color. The brightest and most valuable “red” is termed pigeon blood-red, and are much more valuable that rubies of similar quality. After color follows clarity: similar to diamonds, a clear stone will be more valuable, but a ruby without any needle-like rutile inclusions may indicate that the stone has been treated to enhance the color. Finally, the cut of the stone and its size (measured in carats) also determines price.

Rubies have a hardness of 9.0 on the Mohs scale of mineral hardness. Among the natural gems only moissanite and diamond are harder, with diamond at the top of the list.

Mining
The main source of rubies was the Mogok Valley in Upper Myanmar (Burma). That region has produced some of the finest rubies ever mined, but in recent years very few good rubies have been found there. The new source is in central Myanmar. The area of Mong Hsu began producing rubies during the 1990s and is now the world’s main ruby mining area.

Rubies of lesser quality are found in Thailand, Cambodia, Tanzania, Madagascar, Vietnam, Nepal, Tajikistan, and Pakistan. A few rubies have been found in the U.S. states of Montana, North Carolina, and South Carolina. More recently, large ruby deposits have been found under the receding ice shelf of Greenland. Rubies were found in the Waseges River area of Kenya in 2002.

Spinel, another red gemstone, is sometimes found along with rubies in the same gem gravel or marble, and is even mistaken fo ruby on occasion.

Traditionally, it is women who dive for pearls in Japan, and they would free dive – rather than using scuba, they’d simply hold their breath for minutes on end while they searched for the appropriate molluscs to bring up to the surface.

In this entry, I’ll talk a bit about pearls.

When a tiny piece of grit works its way into the soft tissue (mantle) of a living shelled mollusk, the mollusk – in this case an oyster, begins secreting calcium carbonate around the grit in order to ease the irritation. This is deposited in concentric layers. Not all pearls are perfectly round..it all depends on the shape of the grit. Those pearls that are not round are called baroque pearls.

The finest quality natural pearls have been highly valued as gemstones and objects of beauty for centuries.

Because it is expensive and a matter of luck to find pearls in the wild, for many decades, cultured pears are made – usually in Japan. Grit of a specific shape is deliberately introduced into the oysters, and the pearls are allowed to grow for a few years. Then the oysters are harvested and the pearls removed.

http://famousdiamonds.tripod.com/famousgems.html

Here’s a list of the gems that are described on the site:

American Golden Topaz
The Bismark Sapphire Necklace
The Black Prince’s Ruby (spinel)
The Chalk Emerald Ring
The Delong Star Ruby
The Gordon Sapphire Necklace
The Gordon Star Sapphire Pendant-Ring
The Guinness Emerald Crystal
The Hixon Ruby Crystal
The Logan Sapphire Brooch
The Mackay Emerald Necklace
The Mandalay Ruby
The Maria Alexandrovna Sapphire Brooch
The Midnight Star Ruby
The Mogok Ruby (also known as the Alan Caplan Ruby)
The Patricia Emerald Crystal
Queen Marie of Romania’s Sapphire
The Reward of Faith Sapphire
The Rosser Reeves Star Ruby
The Ruspoli Sapphire
The Samarian Spinel
The Star of Bombay
The Star of India
The Stuart Sapphire
The Timur Ruby

http://famousdiamonds.tripod.com/

I’m interested in the history of gems and their wearers, so this typie of information is fun to read.

Their holdings also include samplings of related pieces, such as match safes, pen and fruit knives, card cases, and dresser items.

Most of the pieces originated in Providence and its environs.

Unfortunately, their website is rather skimpy when it comes to delineating their collection…they want you to visit, instead.

In order to see the museum, you do need to make an appointment.

The Providence Jewelry Museum is open by appointment.

Email them at info@providencejewelrymuseum.com , or telephone
them at 401-274-0999, or 401-781-3100.

Interestingly, the address below is not listed on their website, presumably because they want to make sure you call for an appointment first.

The address:
1 Spectacle Street
Cranston, RI 02904-2404

In particular, silver superseded gold for the setting for gemstones during the 18th and 19th centuries, because experts felt that silver set off the stones better than the overpowering colors of gold.

Most of the silver used iin jewelry prior to the 1900s was imported from Mexico, Peru, Chile and Bolivia. In the late 1800s, the Comstock Lode of silver was found in west Nevada in the USA, and jewelry production was able to increase dramatically.

Platinum was first discovered in South America. Although it was found to be a strong metal, and never tarnished, it took a while before it became used in jewelry.

Its first use as a setting for diamonds is recorded to have occurred in 1870, and it became very fashionable in the 1920 and 1930s.

The earliest gold was found by panning river beds for it, but by Roman times, open-cast and tunnel mining were used in Europe. And then the New World was discovered, and the Spaniarfs brought great quantities of gold from the conquered nations.

Subsequent gold discoveries
California – 1848
Australia 1851
South Africa – 1880s

Until 1975, the purity of gold was measured in karats, with 24 karat being the purest (and the most seldem used, because of its softness).

After 1975, the term used became “Fineness”.

In Europe, for example, pure gold is stamped 1000 fine. 18K is 75 percent or 750 fine. So, an 18K ring made in Europe would be stamped 750.