government passed law in July 2010 that requires companies that sell gemstones to determine the origins of their stones.可知为什么美国政府要求出售宝石的公司确定宝石的来源,是为了减少血矿石的交易。选C 【小题3】细节理解题。从文章第五段的句子:but McManus and her team say that gemstones from the ...
Selection of Specific Gemstone Varieties:The impact of color zoning varies from one gemstone variety to another. Some gemstones, such as tourmaline, tanzanite, and bicolored sapphire, have zoning patterns that are considered attractive and add to the value of the gemstone. In contrast, other gems...
Such rough diamonds are cut and polished to produce the prized glittering stones that are used for jewelry. Diamonds are the hardest known naturally occurring substance and cutting diamonds requires highly skilled craftspeople. The crystal structure of a rough diamond must be carefully assessed in ...
Buy loose Tiger's Eye Matrix gemstones at wholesale prices. Shop for this special type of Tiger's Eye with iron oxide layers that give a deep dusky brown tone to the gemstones. The large cabochons are especially good for pendants and for men's jewelry items. In Stock: 170 Topaz Large ...
Amber occurs in a range of different colors. As well as the usual yellow-orange-brown that is associated with the color “amber”, amber itself can range from a whitish color through a pale lemon yellow, to brown and almost black. Other uncommon colors include red amber (sometimes known as...
Baltic Amber Brown Cognac Teething Bracelet Eur2.65 - Eur5.00 Choose Options Quick view Amber Cognac Baroque Baby Necklace Eur5.10 - Eur10.80 Choose Options Quick view Amber Unpolished Cognac Teething Bracelet Eur2.65 - Eur4.50 Choose Options
These structures produce the banded patterns that are characteristic of many agates. Some of these cavities are lined with crystals and those are known as geodes. Agate occurs in a wide range of colors, which include brown, white, red, gray, pink, black, and yellow. The colors are caused ...
Get to know about gemstones with these worksheets that include their properties, history, and more. Click to download Gemstone Worksheets in PDF or Google slides for school and home.
Welcome to GlitteringStones.com , this is an amazing site for those who are studying gemology. A gem or gemstone is also called precious or semi-precious stone which is a small piece of precious mineral that is polished and then used in making jewellery
Diaspore is a mineral that is typically found in bauxite deposits and is best known for its color-changing variety, also known as Zultanite or Csarite. The color of diaspore can vary from yellow-green to pinkish-brown, but it's the color change that makes it truly unique. ...