Gemstone Measurement: Carats, Weight & Identification

Question
1) Is coral considered a gemstone? Would it be measured in carats.

2) Which of the following are typically measured in carats:
Amazonite
Amethyst
Chalcedony
Citrine
Garnet
Jasper
Labradorite
Lapis Lazuli
Moonstone
Opal
Peridot
Quartz
Ruby
Serpentine
Tiger Eye
Topaz
Tourmaline

3) For those above that are measured in carats, is there a way of converting their regular weight (say, in grams) to a carat measurement?

4) I also saw a necklace made of cowbone. What is a typical way to measure/compare this material?

Answer
Hi Lee,

Some may consider coral as a gemstone but I do not.  But it is used like gemstone materials.  So I guess it could go either way.  As far as carats that is a unit of weight.
All the above can be weighed that way or you can convert to grams.  One gram equals 5 carats.  So one carat would be 200 milligrams.  I think cowbone would be weighed in grams.  Carats are mostly for gemstones and diamonds.


I hope this helps you.

Regards,

Steven D.Covey