The crown, called the St. Wenceslas crown, was made 1347 and has a weight of abt. 2.400 grams, 21/22 ct and is decorated with 20 pearls, rubelit, aquamarine, 16 sapphires, 25 emeralds and 25 spinels.
The orb is from 18 ct gold and has a weight of 780 grams. The decoration is: 6 spinels, 8 sapphires and 31 pearls.
The sceptre is also made from 18 ct gold, weight abt. 1.000 grams and is set with 4 sapphires, 5 spinels and 62 pearls. Last two mentioned are from first half of the 16th century.
The most of emeralds and sapphires are from Sri Lanka (Ceylon).
It’s worth mentioning that Charles IV, who ordered to make this crown, and for him so characteristic, have placed a relic (in the cross) on the top of the crown under the sapphire – a thorn from Christ crown.

The Czech coronation jewels are kept since 1791 at Prague Castle in the Crown Chamber above the south entrance hall of the St. Vitus Cathedral and are showed to the public only on special occasions. This was decided by Charles IV at the time.
To open the Crown Chamber you need seven keys, which are in possession of the following people: the president of the Republic, the prime minister of the government, the archbishop of Prague, the Chamber of Deputies, the president of the Senate, the Metropolitan Chapter of St. Vitus and the mayor of Prague.
Small pictures: Right view of the crown and a details of the orb.