Camellia Diamonds are exclusively sold through 「ジュエリーマキ」 stores throughout Japan with the CMs promoting the flagship Ginza location (座じゅわいよ・くちゅーるマキ) mostly. Sometimes 「ブティックJOY」 was mentioned in later CMs but I'm not sure why it periodically changed.
Miki Corporation has a long history of using great pop music for its promotional campaigns. Among some of the songs in which they have used for past campaigns include KATSUMI's 「危険な女神」 , 中西圭三 「ウーマン」 , アン・ルイス's 「天使よ故郷を見よ」 , TMN's 「LOVE TRAIN」, 久宝留理子's 「男」, 華原朋美's 「LOVE IS ALL MUSIC」, 久保田利伸's 「Honney B」, 中西圭三's 「YOU & I」, 高橋理奈's 「NEOfilia」, 相川七瀬's 「恋心」, and 華原朋美's 「I wanna go」 among others.
In addition to great songs, Miki Corporation also secured some fairly notable U.S. stars for its various CMs including Susan Anton, Farrah Fawcett, Lea Thompson, Diane Lane and Bruce Willis.
Julia would switch record companies several times in the next couple of years before finally landing with independent label ウェーブマスター where she is still currently contracted with.
Interestingly Julia's real name is 豊田樹里/Toyota Julia. Not sure if her stage name is a tongue-in-cheek reference to Toyota's rival auto manufacturer but it sure is a quirky name play.
Due to copyright issues, I wasn't able to find any full length videos on YouTube featuring 「黙ってないで」so instead here is a link to the FC2動画 site which has her PV there.
Here are some more cool 「カメリアダイヤモンド」 CMs -