Do you know what is the hardness of a gem?

Gemstones have a glamorous appearance. Each gem has different hardness due to its different compositional elements. So what do you know about gem hardness? What is the hardness of the stone? Unlike plasticine and cement walls, the hardness of the gemstones we refer to is

Button raw material 68 copper and 62 copper

Today, China Button Industry Network introduces two common materials for copper buttons: 68 Copper: The complete standard method is H68, which is the grade of high-quality brass. It is the most widely used type of brass. It represents 67.0-70.0% of lead and ≤ 0.03 lead. It us

Do you know the basics of 9 silver jewelry?

Why do you know that silver jewelry is not sold by gram, silver is illuminated in the light for a long time, why is it black, and so on? 1. Why are silver ornaments not sold in grams? Because the silverware is sold, it not only reflects its own value, but also has a part

INMAN Yinman Women 2018 Summer White Mijas Series New

The flowers, the sun, and the fairy-tale white houses, the Mikhas, who are beloved by the sun, planted ceramics and flowers on the walls. The girl in a red dress lay in the arms of Prince Charming. The white town of Mijas seems to be the ideal place for Haizi poems to “face the sea and bloom