search
  • Войти
    Зарегистрироваться
  • English speaking customer support only

    Бесплатно - только для США и Канада:
    1-800-464-1640

    Международный:
    +66-39303404

  • Изменить язык
  • USD

How Big Is That Gem?

One of the most common mistakes made by gemstone buyers is selecting a gem based on carat weight rather than size. Most people are familar with diamonds, and have a good idea of the size of a 1 carat brilliant-cut diamond. But if you buy a 1 carat sapphire, you are likely to be disappointed if you expect it to be the same size as your 1 carat diamond. The sapphire will appear substantially smaller.

Same Size - Different Weight
6mm Diamond 0.82ct
6 mm Diamond 0.82 ct
6mm Sapphire 1.48ct
6 mm Sapphire 1.48 ct

There are two reasons for this. First, sapphire is a denser material than diamond. Since the different gemstone varieties have different chemical compositions, they vary with respect to their density or specific gravity. Diamond is not a particularly dense material as far as gemstones go, and a number of gemstones have a higher density, including sapphire, ruby, spinel, garnet and zircon. On the other hand, some gems such as tourmaline, emerald and quartz have a substantially lower density than diamond, and will appear larger in the same carat weight.

The second reason why a 1 carat sapphire will appear smaller than a 1 carat diamond has to do with cutting style. Diamonds are cut to maximize brilliance, while colored gems are cut to maximize color. Diamonds have a larger "face-up" size, since they are cut with a large crown and a small pavilion. Colored gems like sapphires are cut with different proportions; smaller crowns and larger pavilions. This approach results in a richer color.

If you are careful to check the size when purchasing a gemstone, you will never go wrong, since a 6 mm round stone is always 6 mm, regardless of its weight. A 6 mm round ideal-cut diamond will weigh about 0.80 carats. But a 6 mm round sapphire may weigh anything from 1.2 to 1.4 carats.

If you are buying a colored gem to fit a jewelry setting, it is especially important to buy by size rather than carat weight. A jeweler can make a custom setting to fit any size of gem, but manufactured jewelry settings come in standard or calibrated sizes. You will find calibrated sizes for many different gemstone shapes, including round, oval, pear, marquise, octagon, square and heart.

  • Впервые опубликовано: July-11-2009
  • Последняя редакция: January-23-2019
  • © 2005-2020 GemSelect.com Все права защищены.
    Копирование (текста или графики) без письменного согласия GemSelect.com (SETT Company Ltd.) строго запрещено.
More Shapes
Популярные Драгоценные камни
  • Сапфир
  • Изумруд
  • Рубин
  • Аквамарин
  • Циркон
  • Опал
  • Топаз
  • Турмалин
  • Гранат
  • Аметист
  • Цитрин
  • Танзанит
Все драгоценные камни (145)
Main Categories
  • Новые Поступления
  • Лоты Камней
  • Калиброванные Драгоценные Камни
  • Gemstones By Piece
  • Камни Высшего Сорта
  • Сочетающиеся Пары Камней
  • Кабошон
  • Drilled Gems, Briolettes and Beads
  • Камни, по месяцам рождения
  • Резные Драгоценные Камни
  • Причудливые Драгоценные Камни
  • Звездчатые Драгоценные Камни
  • Неподогретые Сапфиры
English speaking customer support only

Бесплатно - только для США и Канада:
1-800-464-1640

Международный:
+66-39303404

Экономьте на доставке! Вы можете купить несколько товаров и заплатить за доставку всего $8.90

Update Translation
 
Current Value
New Value
GemSelect Gemstones
X Закрыть окно
Colored Gemstones
X Закрыть окно
Colored Gemstones
X Закрыть окно
Colored Gemstones
Размер и Вес

Gems are always measured in Millimeter (mm)

Dimensions are given as;
length x width x depth,
except for round stones which are;
diameter x depth

Select gems by size, not by weight!
Gem varieties vary in density, so carat weight is not a good indication of size

Note: 1ct = 0.2g

Size Comparison Chart