kerbent on Family Tree Circles

There is an unusual headstone for one of my ancestors John Thomas in Eaglehawk Cemetery, Eaglehawk, Victoria, Australia.

It is unusual because it has ceramic tiles inlaid into the headstone that are quite ornate.

The headstone has three sections

The top section reads
In / loving memory / of / John Thomas / aged 70 years, / born in Devonshire, / Died at Sandhurst / May 22nd 1879 / The faith the conquers all, / And doth the mountains move, / And saves who'er on Jesus call, / And perfects them in love.

The section carved into the granite below the tiled section
Also / Maragaret Thomas / unable to read next four lines that are engraved into the granite under the tiled decorative section of the headstone

Bottom section an atached cement plaque
Greatly beloved / by their children

According to his death certificate, the informant was his son Michael Thomas he was born in Tavistock, Cornwall.(source John Thomas Death Certificate Year 1879 registration #4501)

I would like to know if it was common for people born in this region to have their headstones decorated with ceramic tiles?
I feel there must be some significance with the tiles but am not sure what it could be and would interested in other peoples thoughts or ideas on the subject?
I would also be interested in making contact with anyone connected to John Thomas and his family.

Sandra