As An Ri Ard wrote, the kingdom of Spain never had a coronation cerimony but an Enthronement during which the new king is proclamed officially, take an oath and receives the oath and the homage from the Greats of Spain, officials and other important person of realm. Today the cerimony take place at the Parliament, the new king take an oath on the constitution and take a speech.
During the Enthronement cerimony on a pillow appears the crown and the scepter.
The royal regalia of Spain had been destroyed during the fire of royal palace in 1734's christmas eve. After this, no crown was created more but, during the reign of queen Isabel II, beginning to be used a old crown known as Corona tumular de los reyes de Espań (funeral crown of kings of Spain).
Some sources want the crown was made during XVIII sec. for king Chales III, others want that it was made in 1766 for the funeral of queen Elisabetta Farnese, wife of king Philip V and mother of king Charles III.
The crown was made by silversmith Fernando Velasco with golden silver. It is really too big to be worn. The height is 39 cm; the greater diameter is 40 cm and the smallest is 18,5 cm. The weight is about 1 kg.
Around the crown you can see the Lion (Léon's arms); Pomegranate (Granada's arms); Castle (Castiglia's arms); 7 Lilies and Eagle. This last symbols are not clear to me.
Spain have not eagles in his coat of arms but only during Francisco Franco's dictatorship. So this eagle could be the arms of kingdom of Sicily.
The lilies are the arms of house of Bourbon, but 3 not 7.
7 lilies are also the arms of the duchy of Parma e Piacenza.
Charles III was duke of Parma e Piacenza (1731-1735), king of Neaples and Sicily (1734-1759) and than king of Spain (1759-1788). So I think that this crown was originally made for this king's funeral.
The royal sceptre was originally a commander's mace made in XVI sec. as a gift from the emperor Rudolf II to his cousin king Philip II but some sources want this mace as a russian gift to king Charles II.
The sceotre is made with silver, enamels, garnets and crystal. It is long 68 cm.