Maltese cross necklace pendant was made in Ukraine by ukrainian jewellers.

The Maltese cross is an octagonal cross of the knightly and monastic order of the Hospitallers, which owned Malta. It comes from the star of Solomon, or from the coat of arms of the Italian city of Amalfi, the natives of which were the founders of the Jerusalem hospital that started the order. A symbol of chastity and the eight knightly virtues.

Chivalric Virtues—
faith
mercy
truth
justice
saintliness
humility
sincerity
patience

The four directions of the cross spoke of the main ones
christian virtues -
prudence
justice
fortitude
restraint

In Ukraine during the development of the Hetmanate, rather close ties developed between the Order of Malta and Zaporizhzhya Sich. Although the Order of Malta officially appeared on Ukrainian lands in 1609, contacts took place even earlier. Hetman Dmytro Vyshnevetskyi, who organized Zaporizhzhya Sich, built it on the model of the Order of Malta. One of the confirmations of this is the image of Maltese crosses on Cossack flags and other paraphernalia, as well as Maltese crosses carved from stone on Cossack graves.
In astronomy, a cross in a circle is a symbol of the Earth, its world with four directions. And according to the myths about the origin of the world from the World Egg, such a sign symbolizes birth.
A circle with a dot in the center is a symbol of a complete temporal cycle. In astrology, the circle is a symbol of the Sun, and in alchemy, it is a symbol of the Sun and the Moon.
The circle inside which the cross is placed means Paradise and its four rivers flowing from the center, as well as the Tree of Life.
This Ukraine locket is made of brass by casting, engraving and polishing
From ancient times, it was believed that the cross is a symbol of the unity of the four earthly elements: earth and fire, air and water. The large cross necklace also reveals the relationship between time and space, energy and information. Сross is a sign of human harmony with the world.
This maltese brass cross is an example of high-quality handmade Ukrainian brass jewelry.

Dimensions of cross in a circle necklace pendant: 34x43 mm (1.4" x 1.7"), weight is about 12.5 g