An eighteenth century Iberian pendant/slide, featuring table cut diamonds set closed-back in 15k gold in the form of a cross, with original slide to the reverse, circa 1790, markings indiscernible, length 3.5 in. 

The eighteenth century was known as the 'Age of the Diamond,' since the techniques necessary for cutting diamonds into desirable shapes became more widely available. The earliest form of cut diamonds is the table cut diamond, simple in that it involved grinding off one pointed end of the rough diamond. These table cut diamonds were often set into gold settings where the gold was rubbed over the stone to hold it in place in a closed-back setting. These jewels were shaped into elaborate crosses, pendants, and chokers. During the Georgian period it was popular to wear necklaces high on the neck, secured with an elaborately tied ribbon at the back of the neck.