Chalcedony

Shopping on line can be easy, simple and save you lots of money. It can also take a lot of your time, frustrate you, and result in unwanted purchases. Now the same can be said for regular high street shopping, but with the vast opportunity presented by the Internet it will pay you to spend a few minutes reading this and understanding how to better optimize your Chalcedony shopping experience:

1. Compare - without doubt the biggest advantage that the Chalcedony offers shoppers today is the ability to compare thousands of Chalcedony at a time. This is a great thing, but not necessarily all the time! Too much can be daunting at times so take advantage of the great comparison sites and where possible let them do the hard work for you.

2. Research - if it has been said it will be on the internet. Ignorance is no longer a justifiable reason for buying the wrong thing. Take the time to research in detail everything that you could possible want to know about

3. Testimonials - don't know anybody that has bought a Chalcedony? Wrong! If the Chalcedony is good the internet will let you know. Use the Internet as a friend and get testimonials before you buy.

4. Questions - Got a question about Chalcedony then search the Forums, FAQ's, Blogs etc. Don't be afraid to ask .....

5. Reputation - Never heard of the company selling Chalcedony? Don't worry, no reason why you should know every company in the world, but you know someone that does! Use the internet to find out what people are saying about Chalcedony and build up a picture of their reputation for sales, returns, customer service, delivery etc.

6. Returns - still worried that even after all of the above your Chalcedony wont be what you want? Check out the returns policy. There is so much competition now that someone, somewhere is bound to offer the terms that you are comfortable with.

7. Feedback - happy with your Chalcedony then let people know, after all you are depending on others people input in your buying decision, so why not give a little back.

8. Security - check for the yellow padlock on the Chalcedony site before you buy, and the s after http:/ /i.e. https:// = a secure site

9. Contact - got a question about Chalcedony, or want to leave a comment then check out the sites contact page. Reputable companies have them and respond.

10. Payment - ready to pay for your Chalcedony, then use your credit card or PayPal! Be aware of companies that don't accept them, there may be genuine reasons but given the huge amount of choice you have when buying online there is no reason at all not to buy via credit card or PayPal.

Chalcedony is a cryptocrystalline form of silica, composed of very fine intergrowths of the minerals quartz and moganiteHeaney, Peter J., 1994. Structure and Chemistry of the low-pressure silica polymorphs. In: Reviews in Mineralogy v. 29; Silica: Physical Behavior, geochemistry and materials applications. Ed. Heaney, P.J., Prewitt, C.T., Gibbs, G.V., 1-40.. These are both silica minerals, but they differ in that quartz has a trigonal crystal structure, whilst moganite is monoclinic. Chalcedony has a waxy lustre, and may be semitransparent or translucent. Its color is usually white to gray, grayish-blue or a shade of brown ranging from pale to nearly black. Other shades have been given specific names: A clear red chalcedony is known as carnelian or sard. A green variety colored by Nickel(II)_oxide is called chrysoprase. Prase is a dull green. Onyx has flat black and white bands. Plasma is a bright to emerald-green chalcedony that is sometimes found with small yellow spots of jasper. Heliotrope is similar to plasma, but with red spots of jasper, hence its alternative name of bloodstone. Chalcedony with concentric banding is known as agate. Flint is also a variety of chalcedony. head, 2nd Century ADPeople living along the Central Asian trade routes used various forms of chalcedony, including carnelian, to carve intaglios, ring bezels (the upper faceted portion of a gem projecting from the ring setting), and beads that show strong Graeco-Roman influence. Fine examples of first century objects made from chalcedony, possibly Kushan, were found in recent years at Tillya-tepe in north-western Afghanistan. Hot wax would not stick to it so it was often used to make Seal (device) impressions.

The term chalcedony is derived from the name of the ancient Greek language town Chalkedon in Asia Minor, in modern English usually spelled Chalcedon, today the Kadıköy district of Istanbul.

Geochemistry: Chalcedony Chalcedony is more soluble than quartz under low-temperature conditions, despite the two minerals being chemically identical. This is thought to be due to the fact that chalcedony is extremely finely grained (cryptocrystalline), and so has a very high surface area to volume ratio.

Solubility of quartz and chalcedony in pure water This table gives equilibrium concentrations of total dissolved silicon as calculated by PHREEQC using the llnl.dat database.TemperatureQuartz Solubility (mg/L)Chalcedony Solubility (mg/L)0.01ºC0.681.3425.0ºC2.644.9250.0ºC6.9512.3575.0ºC14.2124.23100.0ºC24.5940.44

References

See Section 12 of the translation of Weilue - a 3rd century Chinese text by John Hill under "carnelian" and note 12.12 (17)