Victorian Archaeological Revival pendant

I haven't been buying much jewelry since retiring, but this lovely pendant called to me, especially as it is in its original fitted leather box. It is definitely Victorian Archaeological Revival and has a flavor of Castellani and Giuliano, but, based on its fitted case, it is likely the work of Robert Phillips.

The pendant is 18K gold with wonderful ovals of teal, white, and green enamel. There are multiple types of twisted and granulated goldwork around the banded agate and some of the enamel has individual gold granules. There is a compartment containing hair in the back. I would circa date this to the 1860s. The pendant is 3" long and the central section is 1 1/4" in diameter. Unfortunately, the chain for the pendant is gone... ;-(

The box is marked on the inside of the lid:

[Crown symbol]
Phillips
23 Cockspur St
London

Phillips Brothers, also known as Robert Phillips, was founded by Robert and his brother Magnus at some point before 1839. According to the 1841 census, Magnus was much older than Robert (40 to his 26), and was classified as a silversmith, whilst Robert was a watch maker. Magnus died in 1847, and the 1851 census records Robert, by now 36, as having been born in Abergavenny, Monmouth, and describes him as a goldsmith and jeweller. Magnus’s place in the business is later filled by Robert’s son, Alfred (born 1845/46). In 1869 the name of the firm changes to Phillips Brothers & Son to reflect Alfred’s becoming a partner with his father; he takes over completely in 1884, Robert having died in 1881.

Mary Haweis mentions ‘Messrs Phillips of Cockspur Street’ in her 1878 book, The Art Of Beauty: ‘Under the direction of Messrs Phillips, the most perfect models are sought for the ornaments they furnish. Museums and picture galleries are ransacked for devices of necklaces, earrings and pendants…. I saw facsimiles of exquisite Etruscan and Greek collars in gold, every detail being carefully studied, and reproduced after the manner of the ancients.’