Guinea sand is glutinous rice.

Jinia sand is a dialect word in some parts of Hunan (Changsha, Yueyang, etc.). It's glutinous rice. Glutinous rice Baba is a traditional pastry in Hunan, which is made of glutinous rice and has a soft, sweet and fragrant taste. In some local dialects in Hunan, glutinous rice is called Jinia sand, which is a common name for this kind of food by local people.

Ciba is popular in southern China. Guizhou, Chongqing, Sichuan, Jiangxi, Hunan, Fujian, Hubei, Guangdong, Guangxi, Shaanxi and other provinces and cities, and Xinyang, Henan (Luoshan, Guangshan, Huangchuan), Jiujiang, Jiangxi and Nanping, Fujian are the most popular, among which Wuzhou, Guangxi is the most special. Ciba is also the most popular food in Hakka area. People are used to making it on festivals or when food is harvested, which symbolizes celebration, reunion and harvest. Ciba is made of glutinous rice, and its characteristics are sticky, tough, smooth and fragrant.

Other explanations of nia:

nia (flat voice) generally means "no" in Xingtai, Hebei Province, for example, "NIA is at home and NIA has dinner". You can write "nia Ya" with the same pronunciation as "Ni Ya". When you pronounce it, you can pronounce "Ni Ya" as one sound, indicating a slightly blaming tone, which is common in Changzhi and other Shanxi areas.

in Taiyuan and Hohhot dialect, the word "renjia" is pronounced nia (softly) quickly, and this word has no entity. In Jianghuai area, it is often used as a modal particle, and the common meaning is "Did XX", such as "Have you eaten nia" and "Have you got home nia". Entity word is unknown.

in the west of Shandong, south of Hebei and northeast of Henan, such as Shexian, Dongping and Taiqian counties, the junction of two counties in southeast Gaocheng, Shijiazhuang, Hebei, Xiaozhang village in Xinji, Hebei, most villages in the northeast of Jinzhou, and some areas in Taiqian county, Henan Province, some villages in the south of Dingzhou call their mother not nia (pronounced four tones). This Chinese character has not been found. There is a saying that "Damn it" is fast reading.